Online Etymology Dictionary

individual (adj.): early 15c., "one and indivisible, inseparable" (with reference to the Trinity), from Medieval Latin individualis, from Latin individuus "indivisible," from in- "not, opposite of" (see in- (1)) + dividuus "divisible," from dividere "divide" (see divide). Original sense now obsolete; the word was not common before c. 1600 and the 15c. example might be an outlier. Sense of "single, separate, of but one person or thing" is from 1610s; meaning "intended for one person" is from 1889.
inequality (n.): early 15c., "difference of rank or dignity," from Old French inequalité (14c., Modern French inégalité) and directly from Medieval Latin inaequalitas, from Latin inaequalis "unequal, unlike, different (in size); changeable, inconstant," from in- "not, opposite of" (see in- (1)) + aequalis "equal" (see equal). In reference to magnitude, number, intensity, etc., from 1530s.
inexplicable (adj.): early 15c., from Middle French inexplicable or directly from Latin inexplicabilis "that cannot be unfolded or disentangled, very intricate," figuratively, "inexplicable," from in- "not, opposite of" (see in- (1)) + explicabilis "that may be explained" (see explicable).

As a noun, 1745, "something that cannot be explained;" jocular inexplicables "trousers" is from 1829. Related: Inexplicably; inexplicability.
infest (v.): late 15c., "to attack, assail, hurt, distress, annoy," from Old French infester (14c.), from Latin infestare "to attack, disturb, trouble," from infestus "unsafe, hostile, threatening, dangerous," originally "inexorable, not able to be handled," from in- "not, opposite of" (see in- (1)) + -festus "(able to be) seized." Sense of "swarm over in large numbers, attack parasitically" first recorded c. 1600. Related: Infested; infesting.
infinite (adj.): late 14c., "eternal, limitless," also "extremely great in number," from Old French infinit "endless, boundless" and directly from Latin infinitus "unbounded, unlimited, countless, numberless," from in- "not, opposite of" (see in- (1)) + finitus "defining, definite," from finis "end" (see finish (v.)). The noun meaning "that which is infinite" is from 1580s.
infirm (adj.): late 14c., "weak, unsound" (of things), from Latin infirmus "weak, frail, feeble, not strong or firm" (figuratively "superstitious, pusillanimous, inconstant"), from in- "not, opposite of" (see in- (1)) + firmus "strong; stable," figuratively "constant, trusty" (see firm (adj.)). Of persons, "not strong, unhealthy," first recorded c. 1600. As a noun from 1711.
inflect (v.): early 15c., "to bend inward," from Latin inflectere (past participle inflexus) "to bend in, bow, curve," figuratively, "to change, alter, influence," from in- "in" (see in- (1)) + flectere "to bend" (see flexible). Grammatical sense "to vary by change of form" (especially at the end of a word) is fromd 1660s. Related: Inflected; inflecting.
inflexible (adj.): late 14c., "incapable of being bent, physically rigid," also figuratively, "unyielding in temper or purpose," from Middle French inflexible and directly from Latin inflexibilis "that cannot be bent," from in- "not, opposite of" (see in- (1) + flexibilis "pliant, yielding" (see flexible). In early 15c. an identical word had an opposite sense, "capable of being swayed or moved," from in- "in, on." Related: Inflexibly.
inarticulate (adj.): c. 1600, "not clear or intelligible" (of speech); "not jointed or hinged, not composed of segments connected by joints" (in biology), from Late Latin inarticulatus "not articulate, not distinct," from in- "not" (see in- (1)) + articulatus, past participle of articulare "to separate into joints; to utter distinctly" (see articulation). Of persons, "not able to speak clearly," 1754. Related: Inarticulately; inarticulateness; inarticulable.
incapacity (n.): 1610s, "lack of ability, powerlessness," from French incapacité (16c.), from Medieval Latin incapacitatem (nominative incapacitas), from Late Latin incapax (genitive incapacis) "incapable," from in- "not" (see in- (1)) + Latin capax "capable," literally "able to hold much," from capere "to take" (see capable). As a legal term (1640s), "lack of qualification," referring to inability to take, receive, or deal with in some way.
inconvenient (adj.): late 14c., "injurious, dangerous," also "absurd, illogical" (senses now obsolete), from Latin inconvenientem (nominative inconveniens) "unsuitable, not accordant, dissimilar," from in- "not, opposite of" (see in- (1)) + convenientem (see convenient). In early 15c., "inappropriate, unbecoming, unnatural;" also, of an accused person, "unlikely as a culprit, innocent." Sense of "troublesome, incommodious, awkward" first recorded 1650s.
incorrect (adj.): early 15c., "uncorrected, not chastened into obedience," of sinners, etc. (a sense now obsolete), from Latin incorrectus "uncorrected, not revised," from in- "not" (see in- (1)) + correctus, past participle of corrigere "to put straight; to reform" (see correct (v.)). Sense of "not in good style" is from 1670s; that of "factually wrong, erroneous, inaccurate" is from 1750s (implied in incorrectly).
incorrigible (adj.): mid-14c., "incurable (of diseases, venom, etc.); extravagant (of expense); implacable (of hearts)," from Old French incorrigible "perfect, beyond rebuke or discipline" (14c.) or directly from Latin incorrigibilis "not to be corrected," from in- "not, opposite of" (see in- (1)) + corrigibilis, from corrigere "to correct" (see correct (v.)). From mid-15c. as "incapable of improvement" (of persons). Related: Incorrigibly. As a noun, from 1746.
incroyable (n.): 1796, from French incroyable, literally "incredible" (15c.), from in- "not, opposite of, without" (see in- (1)) + croire "to believe," from Latin credere (see credo). A name for the French fop or dandy of the period of the Directory (1795-99). Said to be so called from their extravagant dress, and also, according to OED, from a favorite expression among them ("C'est vraiment incroyable").
indecent (adj.): 1560s, "unbecoming, in bad taste," from French indécent (14c.) or directly from Latin indecentem (nominative indecens) "unbecoming, unseemly," from in- "not, opposite of, without" (see in- (1)) + decens (see decent). Sense of "offending against propriety" is from 1610s. Indecent assault (1861) originally covered sexual assaults other than rape or intended rape, but by 1934 it was being used as a euphemism for "rape." Related: Indecently
indefatigable (adj.): 1580s (implied in indefatigably), from French indefatigable (15c.), from Latin indefatigabilis "that cannot be wearied," from in- "not" (see in- (1)) + defatigare "to tire out," from de- "utterly, down, away" (see de-) + fatigare "to weary" (see fatigue (n.)).

Blount's "Glossographia" (1656) has defatigable, which also was in use elsewhere in 17c., but the modern use of defatigable (1948) probably is a jocular back-formation from indefatigable.
indefinite (adj.): 1520s, "not precise, vague," from Latin indefinitus "indefinite," from in- "not, opposite of, without" (see in- (1)) + definitus, past participle of definire (see define). In reference to number, "The term was introduced by Pascal. Descartes distinguished between the indefinite, which has no particular limit, and the infinite which is incomparably greater than anything having a limit. The distinction is considered as highly important by many metaphysicians." [Century Dictionary]
indelicate (adj.): 1670s, "offensive to a refined sense of propriety, beyond the bounds of proper reserve," from in- (1) "not, opposite of" + delicate. Related: Indelicately.
Immorality and indelicacy are different things. Rabelais is indelicate to the last degree, but he is not really immoral. Congreve is far less indelicate, but far more immoral. [James Hadley, "Essays Philological and Critical," 1873]
indemnity (n.): mid-15c., "security or exemption against damage, loss, etc.," from Middle French indemnité (14c.), from Late Latin indemnitatem (nominative indemnitas) "security for damage," from Latin indemnis "unhurt, undamaged," from in- "not, opposite of, without" (see in- (1)) + damnum "damage" (see damn). Meaning "legal exemption" is from 1640s; sense of "compensation for loss" is from 1793. Related: Indemnitor; indemnitee.
malaria (n.): 1740, from Italian mal'aria, from mala aria, literally "bad air," from mala "bad" (fem. of malo, from Latin malus; see mal-) + aria "air" (see air (n.1)). Probably first used by Italian physician Francisco Torti (1658-1741). The disease, now known to be mosquito-borne, once was thought to be caused by foul air in marshy districts. Replaced native ague.
embargo (n.): "order forbidding ships from certain other nations from entering or leaving a nation's ports," 1590s, from Spanish embargo "seizure, arrest; embargo," noun of action from embargar "restrain, impede, arrest, embargo," from Vulgar Latin *imbarricare, from assimilated form of in- "into, upon" (see in- (2)) + *barra (see bar (n.1)). As a verb, from 1640s. Related: Embargoed.
embezzle (v.): early 15c., "make away with money or property of another, steal," from Anglo-French enbesiler "to steal, cause to disappear" (c. 1300), from Old French em- (see en- (1)) + besillier "torment, destroy, gouge," which is of unknown origin. Sense of "dispose of fraudulently to one's own use," is first recorded 1580s. Related: Embezzled; embezzling.
embroil (v.): c. 1600, "throw into disorder," from French embrouillier "entangle, confuse, embroil" (cognate of Italian imbrogliare), from assimilated form of en- "in" (see en- (1)) + brouiller "confuse," from Old French brooillier (see broil (v.2)). Sense of "involve in a quarrel" is first attested c. 1610. Related: Embroiled; embroiling. Embrangle "mix confusedly" is from 1660s.
eminent (adj.): early 15c., from Old French éminent "prominent" (13c.) or directly from Latin eminentem (nominative eminens) "standing out, projecting, prominent, high," figuratively "distinguished, distinctive," present participle of eminere "stand out, project; be prominent, be conspicuous," from assimilated form of ex- "out" (see ex-) + -minere, which is related to mons "hill" (see mount (n.1)). Related: Eminently. Legal eminent domain recorded from 1738.
barrage (n.): 1859, "action of barring; man-made barrier in a stream," from French barrer "to stop," from barre "bar," from Old French barre (see bar (n.1)). Artillery sense is 1916, from World War I French phrase tir de barrage "barrier fire" intended to isolate the objective. As a verb by 1917. Related: Barraged; barraging.
barrel (n.): c. 1300, from Old French baril (12c.) "barrel, cask, vat," with cognates in all Romance languages (such as Italian barile, Spanish barril), but origin uncertain; perhaps from Gaulish, perhaps somehow related to bar (n.1). Meaning "metal tube of a gun" is from 1640s. Barrel roll in aeronautics is from 1927.
carbohydrate (n.): 1851, from carbo-, comb. form of carbon, + hydrate (n.), denoting compound produced when certain substances combine with water, from Greek hydor "water" (see water (n.1)).
The name carbohydrate was given to these compounds because, in composition, they are apparently hydrates of carbon. In structure, however, they are far more complex. [Flood]
waft (v.): c. 1500, transitive, "to move gently" (through the air), probably from Middle Dutch or Middle Low German, ultimately from wachten "to guard" (perhaps via notion of a ship that guards another as it sails), related to waken "rouse from sleep," from Proto-Germanic *waht- (see wake (n.1)). Possibly influenced by northern dialect waff "cause to move to and fro" (1510s), a variant of wave. Intransitive sense from 1560s. Related: Wafted; wafting.
ferret (n.): late 14c., from Old French furet "ferret," diminutive of fuiron "weasel, ferret," literally "thief" (in allusion to the animal's slyness and craftiness), probably from Late Latin furionem (related to furonem "cat," which also meant "robber"), from Latin fur (genitive furis) "thief," probably from PIE *bhor- (which likely also is the source of furtive), from root *bher- (1) "to bear, carry" (see infer). Also from the French word are Dutch fret, German Frett. Ferret-faced is from 1837 (to have ferret-eyes is from 1580s).
ferrule (n.): "metal cap on a rod," 1610s, ferule, earlier verrel (early 15c.), from Old French virelle "ferrule, collar" (12c. Modern French virole), from Medieval Latin viriola "bracelet," diminutive of Latin viriae "bracelets," from a Gaulish word akin to Old Irish fiar "bent, crooked," from PIE *wi-ria-, from root *wei- (1) "to turn, twist" (see wire (n.)). Spelling influenced by Latin ferrum "iron."
carotid (adj.): 1540s, "pertaining to the two great arteries of the neck," from Greek karotides "great arteries of the neck," plural of karotis, from karoun "plunge into sleep or stupor," because compression of these arteries was believed to cause unconsciousness (Galen). But if this is folk etymology, the Greek word could be from kara "head," related to kranion "skull, upper part of the head," from PIE root *ker- (1) "horn, head" (see horn (n.)).
cartel (n.): 1550s, "a written challenge," from Middle French cartel (16c.), from Italian cartello "placard," diminutive of carta "card" (see card (n.1)). It came to mean "written agreement between challengers" (1690s) and then "a written agreement between challengers" (1889). Sense of "a commercial trust, an association of industrialists" comes 1902, via German Kartell, which is from French. The older U.S. term for that is trust (n.). The usual German name for them was Interessengemeinschaft, abbreviated IG.
casual (adj.): late 14c., "subject to or produced by chance," from Middle French casuel (15c.), from Late Latin casualis "by chance," from Latin casus "chance, occasion, opportunity; accident, event" (see case (n.1)).

Of persons, in the sense of "not to be depended on, unmethodical," it is attested from 1883; meaning "showing lack of interest" is from 1916. Of clothes, "informal," from 1939. Related: Casually.
casuist (n.): c. 1600, "one who studies and resolves cases of conscience," from French casuiste (17c.) or Spanish casuista (the French word also might be from Spanish), Italian casista, all from Latin casus (see case (n.1)) in its Medieval Latin sense "case of conscience." Often since 17c. in a sinister or contemptuous sense. Related: Casuistic; casuistical; casuistically; casuistry.
Casuistry ... destroys, by distinctions and exceptions, all morality, and effaces the essential difference between right and wrong. [Bolingbroke, 1736]
add (v.): late 14c., "to join or unite (something to something else)," from Latin addere "add to, join, attach, place upon," from ad- "to" (see ad-) + -dere comb. form meaning "to put, place," from dare "to give" (see date (n.1)). Meaning "to do sums, do addition" also is from late 14c. Related: Added; adding. To add up "make sense" is from 1942.
afanc (n.): cattle-devouring aquatic monster in Celtic countries, from Celtic *abankos "water-creature," from *ab- "water" (source also of Welsh afon, Breton aven "river," Latin amnis "stream, river," which is believed to be of Italo-Celtic origin), from PIE root *ap- (2) "water" (for which see water (n.1)).
deport (v.1): late 15c., "to behave," from Old French deporter "behave, deport (oneself)" (12c.), also with a wide range of meanings in Old French, such as "be patient; take one's (sexual) pleasure with; amuse, entertain; remain, delay, tarry; cheer, console, treat kindly; put aside, cast off, send away," from de- "from, off" (see de-) + porter "to carry," from Latin portare "to carry" (see port (n.1)). Related: Deported; deporting.
depress (v.): early 14c., "put down by force," from Old French depresser, from Late Latin depressare, frequentative of Latin deprimere "press down," from de- "down" (see de-) + premere "to press" (see press (v.1)). Meaning "push down physically" is from early 15c.; that of "deject, make gloomy" is from 1620s; economic sense of "lower in value" is from 1878. Related: Depressed; depressing.
Templar (n.): late 13c., from Anglo-French templer, Old French templier (c. 1200), from Medieval Latin templaris (mid-12c.), member of the medieval religious/military order known as Knights Templars (c.1118-1312), so called because they had headquarters in a building near Solomon's Temple in Jerusalem (see temple (n.1)). Their distinguishing garb was a white mantle with a red cross.
mandate (n.): "judicial or legal order," c. 1500, from Middle French mandat (15c.) and directly from Latin mandatum "commission, command, order," noun use of neuter past participle of mandare "to order, commit to one's charge," literally "to give into one's hand," probably from manus "hand" (see manual) + dare "to give" (see date (n.1)). Political sense of "approval supposedly conferred by voters to the policies or slogans advocated by winners of an election" is from 1796. League of Nations sense is from 1919.
redline (v.): also red-line, "mark in red ink," 1820, from red (adj.1) + line (v.). Specific sense of "deny loans to certain neighborhoods based on ethnicity" is from 1973, on notion of lines drawn on maps. Used earlier in reference to insurance company practices (1961) and in World War II military slang in reference to a red line drawn through a soldier's name for some infraction, thus denying his pay. Related: Redlined; redlining.
reef (n.2): "horizontal section of sail," late 14c. (mid-14c. in rif-rope), from a Scandinavian source such as Old Norse rif "reef of a sail," probably a transferred use of rif "ridge under the sea; rib" (see rib (n.) and compare reef (n.1)). German reff, Swedish ref, Norwegian riv, Danish reb likely all are from the Old Norse word.
paradigm (n.): late 15c., from Late Latin paradigma "pattern, example," especially in grammar, from Greek paradeigma "pattern, model; precedent, example," from paradeiknynai "exhibit, represent," literally "show side by side," from para- "beside" (see para- (1)) + deiknynai "to show" (cognate with Latin dicere "to show;" see diction). Related: Paradigmatic; paradigmatical.
paradox (n.): 1530s, "statement contrary to common belief or expectation," from Middle French paradoxe (14c.) and directly from Latin paradoxum "paradox, statement seemingly absurd yet really true," from Greek paradoxon, noun use of neuter of adjective paradoxos "contrary to expectation, incredible," from para- "contrary to" (see para- (1)) + doxa "opinion," from dokein "to appear, seem, think" (see decent). Meaning "statement that is seemingly self-contradictory yet not illogical or obviously untrue" is from 1560s.
paragon (n.): 1540s, from Middle French paragon "a model, pattern of excellence" (15c., Modern French parangon), from Italian paragone, originally "touchstone to test gold" (early 14c.), from paragonare "to test on a touchstone, compare," from Greek parakonan "to sharpen, whet," from para- "on the side" (see para- (1)) + akone "whetstone," from PIE root *ak- "sharp, pointed" (see acrid).
paragraph (n.): late 15c., from Middle French paragraphe "division of text" (13c., Old French paragrafe), from Medieval Latin paragraphus "sign for start of a new section of discourse" (the sign looked something like a stylized letter -P-), from Greek paragraphos "short stroke in the margin marking a break in sense," also "a passage so marked," literally "anything written beside," from paragraphein "write by the side," from para- "beside" (see para- (1)) + graphein "to write" (see -graphy).
parameter (n.): 1650s in geometry, from Modern Latin parameter (1630s), from Greek para- "beside, subsidiary" (see para- (1)) + metron "measure" (see meter (n.2)).

A geometry term until 1920s when it yielded sense of "measurable factor which helps to define a particular system" (1927). Common modern meaning (influenced by perimeter) of "boundary, limit, characteristic factor" is from 1950s. Related: Parametric.
paranoia (n.): "mental disorder characterized by systematized delusions," 1848 (earlier paranoea 1811), from Greek paranoia "mental derangement, madness," from paranoos "mentally ill, insane," from para- "beside, beyond" (see para- (1)) + noos "mind."
FOR several years frequent descriptions have been given in the foreign journals, especially German and Italian, of the forms of insanity designated by the names Paranoia, Verrücktkeit, and Wahnsinn. ["Paranoia -- Systematized Delusions and Mental Degenerations," J. Séglas (transl. William Noyes), 1888]
paraphernalia (n.): 1650s, "a woman's property besides her dowry," from Medieval Latin paraphernalia (short for paraphernalia bona "paraphernal goods"), neuter plural of paraphernalis (adj.), from Late Latin parapherna "a woman's property besides her dowry," from Greek parapherna, neuter plural, from para- "beside" (see para- (1)) + pherne "dowry," related to pherein "to carry" (see infer). Meaning "equipment, apparatus" is first attested 1791, from notion of odds and ends.
parasite (n.): 1530s, "a hanger-on, a toady, person who lives on others," from Middle French parasite (16c.) or directly from Latin parasitus "toady, sponger," and directly from Greek parasitos "one who lives at another's expense, person who eats at the table of another," from noun use of an adjective meaning "feeding beside," from para- "beside" (see para- (1)) + sitos "food," of unknown origin. Scientific meaning "animal or plant that lives on others" is first recorded 1640s (implied in parasitical).