Online Etymology Dictionary

incessant (adj.): mid-15c., from Old French *incessant or directly from Late Latin incessantem (nominative incessans) "unceasing," from Latin in- "not" (see in- (1)) + cessans, present participle of cessare "to cease" (see cease (v.)). Related: Incessantly (early 15c.).
incommensurable (adj.): "having no common measure," 1550s, from Middle French incommensurable (14c.) or directly from Medieval Latin incommensurabilis, from in- "not, opposite of, without" (see in- (1)) + Late Latin commensurabilis, from Latin com- "with" (see com-) + mensurabilis "measurable," from mensurare "to measure" (see measure (v.)). Related: Incommensurably.
incompatible (adj.): "that cannot coexist or be conjoined," mid-15c., from Medieval Latin incompatibilis, from in- "not, opposite of" (see in- (1)) + compatibilis (see compatible). Originally of benefices, "incapable of being held together;" sense of "mutually intolerant" is from 1590s. Related: Incompatibly.
incompetent (adj.): 1610s, "insufficient," from French incompétent, from Late Latin incompetentem (nominative incompetens) "insufficient," from in- "not" (see in- (1)) + Latin competentem (see competent). Sense of "lacking qualification or ability" first recorded 1630s. The noun meaning "incompetent person" is from 1866. Related: Incompetently.
inconsequent (adj.): 1570s, "not following as a logical conclusion," from Latin inconsequentem (nominative inconsequens) "not logically connected, not resulting from what has preceded," from in- "not, opposite of, without" (see in- (1)) + consequens, past participle of consequi "to follow" (see consequence). Related: Inconsequently.
inconsiderate (adj.): late 15c., "done thoughtlessly, heedless, careless, indiscreet," from Latin inconsideratus "headstrong, unadvised," of persons, "thoughtless," literally "not properly considered," from in- "not, opposite of" (see in- (1)) + consideratus (see consider). Sense of "without regard for the feelings of others" is from 1842. Related: Inconsiderately.
inconspicuous (adj.): 1620s, "invisible," from Late Latin inconspicuus "not conspicuous," from in- "not, opposite of, without" (see in- (1)) + Latin conspicuus (see conspicuous). Weakened sense of "not readily seen or noticed" developed by 1828. Related: Inconspicuously; inconspicuousness.
inconstant (adj.): c. 1400, "fickle, not steadfast," from Old French inconstant "variable, eccentric" (14c.), from Latin inconstantem (nominative inconstans) "changeable, fickle, capricious," from in- "not, opposite of, without" (see in- (1)) + constantem (see constant). Related: Inconstantly.
incredible (adj.): early 15c., "unbelievable, surpassing belief as to what is possible," from Latin incredibilis "not to be believed, extraordinary," from in- "not" (see in- (1)) + credibilis "worthy of belief" (see credible). Used c. 1400 in a now-extinct sense of "unbelieving, incredulous." Related: Incredibly; incredibility.
inculcate (v.): 1540s, from Latin inculcatus, past participle of inculcare "force upon, insist; stamp in, impress, tread down," from in- "in" (see in- (2)) + calcare "to tread, press in," from calx (1) "heel" (see calcaneus). Related: Inculcated; inculcating.
inculpate (v.): "to accuse, bring charges against," 1794, from Medieval Latin inculpatus, past participle of inculpare "to reproach, blame, censure," from Latin in- "in" (see in- (2)) + culpare "to blame," from culpa "fault." But inculpable (late 15c.) means "not culpable, free from blame," from Latin in- "not" (see in- (1)) + culpare.
incurable (adj.): mid-14c., from Old French incurable "not curable" (13c.), from Late Latin incurabilis "not curable," from in- "not" (see in- (1)) + curabilis "curable" (see curable). As a noun, "incurable person," from 1650s. Related: Incurably.
haruspex (n.): 1580s, from Latin haruspex (plural haruspices) "soothsayer by means of entrails," first element from PIE *ghere- "gut, entrail" (see yarn); second element from Latin spic- "beholding, inspecting," from PIE *speks "he who sees," from root *spek- "to observe" (see scope (n.1)). The practice is Etruscan. Related: Haruspical; haruspication.
embattle (v.): late 14c., "prepare for a fight," from Old French embataillier "to prepare for battle," from assimilated form of en- (see en- (1)) + bataille (see battle (n.)). Related: Embattled; embattling. Originally of armies; of individuals as well since 1590s (first attested in Spenser).
embed (v.): 1778, "to lay in a bed (of surrounding matter)," from em- (1) + bed (n.). Originally a geological term, in reference to fossils in rock; figurative sense is by 1835; meaning "place (a journalist) within a military unit at war" is from 2003 and the Iraq war. Related: Embedded; embedding.
embellish (v.): mid-14c., "to render beautiful," from Old French embelliss-, stem of embellir "make beautiful, ornament," from assimilated form of en- (see en- (1)) + bel "beautiful," from Latin bellus "handsome, pretty, fine" (see bene-). Meaning "dress up (a narration) with fictitious matter" is from mid-15c. Related: Embellished; embellishing.
emboss (v.): "to ornament with raised work," late 14c., from Old French *embocer (compare embocieure "boss, stud, buckle"), from assimilated form of en- "in, into" (see en- (1)) + boce "knoblike mass" (see boss (n.2)). Related: Embossed; embossing.
embrasure (n.): "enlargement of the interior aperture of a door or window," 1702, from French embrasure (16c.), from Old French embraser "to cut at a slant, make a groove or furrow in a door or window," from assimilated form of en- "in" (see en- (1)) + braser "to cut at a slant."
vetch (n.): climbing herb, late 14c., from Old North French veche, variant of Old French vece, from Latin vicia, which perhaps is related to vincire "to bind" (compare second element of periwinkle (n.1)). Dutch wikke, German Wicke are loan-words from Latin vicia.
empirical (adj.): 1560s, originally in medicine, "pertaining to or derived from experience or experiments," from empiric + -al (1). In a general sense of "guided by mere experience" from 1757. Related: Empirically (1640s as "by means of observation and experiment").
deploy (v.): 1786 as a military word, from French déployer "unroll, unfold," from Old French desploiier "unfold," from Latin displicare "unfold, scatter," from dis- (see dis-) + plicare "to fold" see ply (v.1)). "In its AFr. form regularly adopted in ME as desplay" [OED]. Related: Deployed; deploying.
despise (v.): c. 1300, from Old French despis-, present participle stem of despire "to despise," from Latin despicere "look down on, scorn," from de- "down" (see de-) + spicere/specere "look at" (see scope (n.1)). Related: Despised; despising.
detraction (n.): mid-14c., from Old French detraccion "detraction, disparagement, denigration," from Latin detractionem (nominative detractio) "a drawing off," from past participle stem of detrahere "take down, pull down, disparage," from de- "down" (see de-) + trahere "to pull" (see tract (n.1)). The fem. form detractress is attested from 1716.
opportune (adj.): c. 1400, from Old French opportun and directly from Latin opportunus "fit, convenient, suitable, favorable," from the phrase ob portum veniens "coming toward a port," in reference to the wind, from ob "to, toward" (see ob-) + portus "harbor" (see port (n.1)). Related: Opportunely.
oppose (v.): late 14c., from Old French oposer "oppose, resist, rival; contradict, state opposing point of view" (12c.), from poser "to place, lay down" (see pose (v.1)), blended with Latin opponere "oppose, object to, set against" (see opponent). Related: Opposed; opposing.
opulence (n.): c. 1510, from Middle French opulence (16c.), from Latin opulentia, from opulentus "wealthy," dissimilated from *op-en-ent-, related to ops "wealth, power, resources," opus "work, labor, exertion," from PIE root *op- (1) "to work, produce in abundance" (see opus).
manicure (n.): 1873, "one who professionally treats hands and fingernails," from French manicure, literally "the care of the hands," from Latin manus "hand" (see manual) + cura "care" (see cure (n.1)). Meaning "treatment and care of the hands and fingernails" is attested from 1887.
reel (v.1): "to whirl around," late 14c., also "sway, swing, rock, become unsteady" (late 14c.), "stagger as a result of a blow, etc." (c. 1400), probably from reel (n.1), on notion of "spinning." Of the mind, from 1796. Related: Reeled; reeling.
parallax (n.): 1570s, from Middle French parallaxe (mid-16c.), from Greek parallaxis "change, alteration, inclination of two lines meeting at an angle," from parallassein "to alter, make things alternate," from para- (see para- (1)) + allassein "to change," from allos "other" (see alias (adv.)). Related: Parallactic.
parallel (adj.): 1540s, from Middle French parallèle (16c.) and directly from Latin parallelus, from Greek parallelos "parallel," from para allelois "beside one another," from para- "beside" (see para- (1)) + allelois "each other," from allos "other" (see alias (adv.)). As a noun from 1550s. Parallel bars as gymnastics apparatus are recorded from 1868.
paraplegia (n.): "paralysis of the lower half of the body," 1650s, Latinized form of (Ionic) Greek paraplegie "paralysis of one side of the body," from paraplessein "strike at the side," paraplessesthai "be stricken on one side," from para- "beside" (see para- (1)) + plessein "to strike" (see plague (n.)).
paregoric (n.): "medicine that soothes pain," 1704, from adjective (1680s) "soothing," from Late Latin paregoricus, from Greek paregorikos "soothing, encouraging, consoling," from paregorein "speak soothingly to," from paregoros "consoling," from para- "beside" (see para- (1)) + root of agoreuein "speak in public," from agora "public assembly," from PIE root *ger- "to gather" (see gregarious).
passport (n.): c. 1500, from Middle French passeport "authorization to pass through a port" to enter or leave a country (15c.), from passe, imperative of Old French passer "to pass" (see pass (v.)) + port "port" (see port (n.1)).
reciprocal (adj.): 1560s, with -al (1) + stem of Latin reciprocus "returning the same way, alternating," from pre-Latin *reco-proco-, from *recus (from re- "back;" see re-, + -cus, adjective formation) + *procus (from pro- "forward;" see pro-, + -cus. Related: Reciprocally. The noun meaning "that which is reciprocal" (to another) is from 1560s.
rectangle (n.): 1570s, from Middle French rectangle (16c.) and directly from Late Latin rectangulum, from rect-, comb. form of Latin rectus "right" (see right (adj.1)) + Old French angle (see angle (n.)). Medieval Latin rectangulum meant "a triangle having a right angle."
rectify (v.): c. 1400, from Old French rectifier, literally "to make straight" (14c.), from Late Latin rectificare "make right," from Latin rectus "straight" (see right (adj.1)) + root of facere "to make" (see factitious). Related: Rectified; rectifying.
rectitude (n.): early 15c., "quality of being straight," from Middle French rectitude (14c.), from Late Latin rectitudinem (nominative rectitudo) "straightness, uprightness," from Latin rectus "straight" (see right (adj.1)). Sense of "upright in conduct or character" is from 1530s.
chandelier (n.): late 14c., chaundeler "candlestick, chandelier," from Old French chandelier (n.1), 12c., earlier chandelabre "candlestick, candelabrum" (10c.), from Latin candelabrum, from candela "candle" (see candle). Re-spelled mid-18c. in French fashion; during 17c. the French spelling referred to a military device.
vital (adj.): late 14c., "of or manifesting life," from Latin vitalis "of or belonging to life," from vita "life," related to vivere "to live," from PIE root *gweie- (1) "to live" (see bio-). The sense of "necessary or important" is from 1610s, via the notion of "essential to life" (late 15c.). Vital capacity recorded from 1852. Related: Vitally.
willy-nilly: c. 1600, contraction of will I, nill I, or will he, nill he, or will ye, nill ye, literally "with or without the will of the person concerned." See nill + will (v.1).
enable (v.): early 15c., "to make fit;" mid-15c., "to make able to," from en- (1) "make, put in" + able. Related: Enabled; enabling. An enabling act (1684) is so called because it empowers a body or person to take certain action.
enamel (v.): early 14c., from Anglo-French enamailler (early 14c.), from en- "in" (see en- (1)) + amailler "to enamel," variant of Old French esmailler, from esmal "enamel," from Frankish *smalt, from Proto-Germanic *smaltjan "to smelt" (see smelt (v.)). Related: Enameled; enameler; enameling.
engorge (v.): 1510s, "fill to excess," from French engorger "to obstruct, block, congest," Old French engorgier "to swallow, devour," from en- (see en- (1)) + gorge "throat" (see gorge (n.)). Probably originally in reference to hawks. Related: Engorged; engorging.
diet (n.2): "assembly," mid-15c., from Medieval Latin dieta, variant of diaeta "daily office (of the Church), daily duty, assembly, meeting of counselors," from Greek diaita (see diet (n.1)), but associated with Latin dies "day" (see diurnal).
omni-: word-forming element meaning "all," from Latin omni-, combining form of omnis "all, every, the whole, of every kind," of unknown origin, perhaps literally "abundant," from *op-ni-, from PIE root *op- (1) "to work, produce in abundance" (see opus).
insatiable (adj.): early 15c., insaciable, from Old French insaciable "ravenous" (15c., Modern French insatiable), or directly from Latin insatiabilis "not to be satisfied," from in- "not, opposite of" (see in- (1)) + satiabilis, from satiare (see satiate). Related: Insatiably; insatiableness.
insecure (adj.): 1640s, "unsafe," also "not fully assured, not free from fear or doubt," from Medieval Latin insecurus, from in- "not" (see in- (1)) + Latin securus (see secure (adj.)). Psychological sense dates from 1935. (insecurity in the psychological sense dates from 1917.) Related: Insecurely.
instability (n.): early 15c., from Old French instabilité "inconstancy" (15c.) or directly from Latin instabilitatem (nominative instabilitas) "unsteadiness," from instabilis "unsteady, not firm, inconstant, fickle," from in- "not, opposite of" (see in- (1)) + stabilis (see stable (adj.)).
insufficient (adj.): late 14c., from Old French insufficient (14c.) or directly from Late Latin insufficientem (nominative insufficiens) "not sufficient," from in- "not, opposite of" (see in- (1)) + sufficientem (see sufficient). Originally of persons, "inadequate, unable;" of things, "lacking in what is necessary or required," from late 15c. Related: Insufficiently.
intemperate (adj.): "characterized by excessive indulgence in a passion or appetite," late 14c., from Latin intemperatus "excessive, immoderate," from in- "not, opposite of" (see in- (1)) + temperatus "restrained, regulated, limited, moderate, sober, calm, steady," past participle of temperare "to moderate" (see temper (v.)). Related: Intemperately.