Online Etymology Dictionary

immaterial (adj.): c. 1400, "spiritual, incorporeal, not consisting of matter," from Medieval Latin immaterialis "not consisting of matter, spiritual," from assimilated form of in- "not, opposite of" (see in- (1)) + Late Latin materialis "of or belonging to matter" (see material (adj.)). Sense of "unimportant, of no consequence" is first recorded 1690s from material (adj.) in its meaning "important" (16c.). Related: Immaterially (late 14c.); immateriality.
immature (adj.): 1540s, "untimely, premature," from Latin immaturus "untimely, unripe," from assimilated form of in- "not, opposite of" (see in- (1)) + maturus "ripe, timely, early" (see mature (v.)). In 16c., usually in reference to early death; main modern sense of "not fully developed" first recorded 1640s. In reference to mentalities or behaviors not considered age-appropriate, from 1920. Related: Immaturely.
immemorial (adj.): c. 1600, from French immémorial "old beyond memory" (16c.), from Medieval Latin immemorialis, from assimilated form of in- "not, opposite of" (see in- (1)) + Latin memorialis of or belonging to memory" (see memorial (n.)). Something immemorial is ancient beyond memory; something immemorable is not worth remembering. Latin immemor meant "unmindful, forgetful, heedless."
imminent (adj.): 1520s, from Middle French imminent (14c.) and directly from Latin imminentem (nominative imminens) "overhanging; impending," present participle of imminere "to overhang, lean towards," hence "be near to," also "threaten, menace, impend, be at hand, be about to happen," from assimilated form of in- "into, in, on, upon" (see in- (2)) + -minere "jut out," which is related to mons "hill" (see mount (n.1)). Related: Imminently.
immortal (adj.): late 14c., "deathless," from Latin immortalis "deathless, undying" (of gods), "imperishable, endless" (of fame, love, work, etc.), from assimilated form of in- "not, opposite of" (see in- (1)) + mortalis "mortal" (see mortal (adj.)). In reference to fame, literature, etc., "unceasing, destined to endure forever, never to be forgotten, lasting a long time," attested from early 15c. (also in classical Latin). As a noun, "an immortal being," from 1680s.
imperfect (adj.): late 14c., imparfit, "sinful, immoral; not properly formed, not complete, immature; rudimentary, elementary," from Old French imparfait, from Latin imperfectus "unfinished, incomplete, immature," from assimilated form of in- "not, opposite of" (see in- (1)) + perfectus "finished, complete" (see perfect (adj.)). Altered mid-16c. to conform to Latin, along with perfect. Related: Imperfectly.
impervious (adj.): 1640s, from Latin impervius "not to be traverse, that cannot be passed through, impassible," from assimilated form of in- "not, opposite of" (see in- (1)) + pervius "letting things through, that can be passed through," from per "through" (see per (prep.)) + via "road" (see via (adv.)). Related: Imperviously; imperviousness.
implication (n.): early 15c., "action of entangling," from Latin implicationem (nominative implicatio) "an interweaving, an entanglement," noun of state from past participle stem of implicare "involve, entangle; embrace; connect closely, associate," from assimilated form of in- "into, in, on, upon" (see in- (2)) + plicare "to fold" (see ply (v.1)). Meaning "that which is implied (but not expressed), inference drawn from what is observed" is from 1550s.
impose (v.): late 14c., "to lay (a crime, duty, obligation, etc.) to the account of," from Old French imposer "put, place; impute, charge, accuse" (c. 1300), from assimilated form of in- "into, in" (see in- (2)) + poser "put, place" (see pose (v.1)). From c. 1500 as "apply authoritatively." Sense of "lay on as a burden, inflict by force or authority" first recorded 1580s. Related: Imposed; imposer; imposing.
imprescriptible (adj.): "inalienable, not subject to law or convention," 1560s, from French imprescriptible (16c.) or a native formation from assimilated form of in- (1) "not, opposite of" + Latin praescriptus, past participle of praescribere "to write beforehand, determine in advance, ordain, dictate" (see prescribe). Usually with right (n.). Related: Imperscriptibility. Alternative imprescribable is attested from 1887.
imprint (v.): formerly also emprint, late 14c., imprenten, emprenten, "to mark by pressure, stamp; to impress on the mind or memory," from Old French empreinter "to stamp, engrave, imprint," from empreinte "mark, impression, imprint" (13c.), noun use of fem. past participle of eimpreindre "to impress, imprint," from Vulgar Latin *impremere, from Latin imprimere "to impress, imprint" (see impress (v.1)).
improper (adj.): mid-15c., "not true," from Old French impropre (14c.) and directly from Latin improprius "not proper," from assimilated form of in- "not, opposite of" (see in- (1)) + proprius (see proper). Meaning "not suited, unfit" is from 1560s; that of "not in accordance with good manners, modesty, or decency" is from 1739. Related: Improperly (late 14c.).
improvisation (n.): "act of improvising musically," 1786, from French improvisation, from improviser "compose or say extemporaneously" (17c.), from Italian improvisare "to sing or speak extempore," from Latin improviso "unforeseen; not studied or prepared beforehand," ablative of improvisus "not foreseen, unexpected," from assimilated form of in- "not, opposite of" (see in- (1)) + provisus "foreseen," also "provided," past participle of providere "foresee, provide" (see provide). From music the sense expanded to a general meaning "do or perform on the spur of the moment."
jackboot (n.): also jack-boot, 1680s, type of large, strong over-the-knee cavalry boot of 17c.-18c., later a type worn by German military and para-military units in the Nazi period. From jack (n.), though the exact sense here is unclear + boot (n.1). Figurative of military oppression since 1768. Related: Jackbooted.
machete (n.): 1590s (in pseudo-Spanish form macheto), from Spanish machete, probably a diminutive of macho "sledge hammer," alteration of mazo "club," which is probably [Barnhart] a dialectal variant of maza "mallet," from Vulgar Latin *mattea "war club" (see mace (n.1)). An alternative explanation traces macho to Latin marculus "a small hammer," diminutive of marcus "hammer," from a base parallel to that of Latin malleus (see mallet).
lamprey (n.): c. 1300 (perhaps c. 1200 as a surname), from Old French lamproie "lamprey" (12c.), from Medieval Latin lampreda, from Late Latin lampetra "lamprey," a word of uncertain origin, usually explained as literally "lick-rock," from Latin lambere "to lick" (see lap (v.1)) + petra "rock" (see petrous), but this might be folk etymology. The animals attach themselves with sucker-like mouths.
lap (v.2): early 14c., "to surround (something with something else)," from lap (n.1). Figurative use, "to envelop (in love, sin, desire, etc.)" is from mid-14c. Meaning "lay one part over another, lay in such a way as to cover part of something underneath" is from c. 1600. The sense of "to get a lap ahead (of a competitor) on a track" is from 1847, on notion of "overlapping" (see lap (n.2)). Related: Lapped; lapping.
prominent (adj.): mid-15c., "projecting, jutting out," from Latin prominentem (nominative prominens) "prominent," present participle of prominere "jut or stand out, be prominent, overhang," from pro- "before, forward" (see pro-) + -minere "project, jut out," which is related to mons "hill" (see mount (n.1)). Meaning "conspicuous" is from 1759; that of "notable, leading" is from 1849. Related: Prominently.
prospect (n.): early 15c., "act of looking into the distance," from Latin prospectus "distant view, look out; sight, faculty of sight," noun use of past participle of prospicere "look out on, look forward," from pro- "forward" (see pro-) + specere "look at" (see scope (n.1)). Meaning "extensive view of the landscape" is from 1530s; transferred sense of "mental view or survey" is from 1620s. Sense of "person or thing considered promising" is from 1922. Prospects "expectations, things looked forward to" is from 1660s.
pucker (v.): 1590s, "prob. earlier in colloquial use" [OED], possibly a frequentative form of pock, dialectal variant of poke "bag, sack" (see poke (n.1)), which would give it the same notion as in purse (v.). "Verbs of this type often shorten or obscure the original vowel; compare clutter, flutter, putter, etc." [Barnhart]. Related: Puckered; puckering.
puerility (n.): late 15c., from Middle French puérilité (15c.), from Latin puerilitatem (nominative puerilitas) "childishness," from puerilis "boyish, youthful; childish, trivial, silly," from puer "child, boy," from PIE *pau- (1) "few, little," with sense extended to "small, young" (source also of Latin putus "boy," Sanskrit putrah "son, boy," Avestan puthra- "son, child;" see few (adj.)).
oblique (adj.): early 15c., from Middle French oblique (14c.) and directly from Latin obliquus "slanting, sidelong, indirect," from ob "against" (see ob-) + root of licinus "bent upward," from PIE root *lei- "to bend, be movable" (see limb (n.1)). As a type of muscles, in reference to the axis of the body, 1610s (adj.), 1800 (n.). Related: Obliquely; obliqueness.
profile (n.): 1650s, "a drawing of the outline of anything," from older Italian profilo "a drawing in outline," from profilare "to draw in outline," from pro- "forth" (see pro-) + filare "draw out, spin," from Late Latin filare "to spin, draw out a line," from filum "thread" (see file (v.1)). Meaning "a side view" is from 1660s. Meaning "biographical sketch, character study" is from 1734.
pulsation (n.): early 15c., from Middle French pulsation (14c.) and directly from Latin pulsationem (nominative pulsatio) "a beating or striking," noun of action from past participle stem of pulsare "to beat, strike, push against' hammer, keep hitting," figuratively "drive forth, disturb, disquiet," frequentative of pellere (past participle pulsus) "to beat, strike" (see pulse (n.1)).
punch (n.2): type of mixed drink, 1630s, traditionally since 17c. said to derive from Hindi panch "five," in reference to the number of original ingredients (spirits, water, lemon juice, sugar, spice), from Sanskrit panchan-s, from pancha "five" (see five). But there are difficulties (see OED), and connection to puncheon (n.1) is not impossible.
purpose (n.): c. 1300, "intention, aim, goal," from Anglo-French purpos, Old French porpos "aim, intention" (12c.), from porposer "to put forth," from por- "forth" (from Latin pro- "forth;" see pur-) + Old French poser "to put, place" (see pose (v.1)). On purpose "by design" is attested from 1580s; earlier of purpose (early 15c.).
pussy (n.1): "cat," 1726, diminutive of puss (n.1), also used of a rabbit (1715). As a term of endearment for a girl or woman, from 1580s (also used of effeminate men). To play pussy was World War II RAF slang for "to take advantage of cloud cover, jumping from cloud to cloud to shadow a potential victim or avoid recognition."
pustule (n.): late 14c., from Old French pustule (13c.) and directly from Latin pustula "blister, pimple," from PIE imitative root *pu- (1) "blow, swell," on notion of "inflated area" (source also of Sanskrit pupphusah "lung," Greek physa "breath, blast, wind, bubble," Lithuanian puciu "to blow, swell," Old Church Slavonic puchati "to blow"). Compare emphysema. Related: Pustulant; pustular.
occasion (n.): late 14c., "opportunity; grounds for action, state of affairs that makes something else possible; a happening, occurrence," from Old French ochaison, ocasion "cause, reason, excuse, pretext; opportunity" (13c.) or directly from Latin occasionem (nominative occasio) "opportunity, appropriate time," in Late Latin "cause," from occasum, occasus, past participle of occidere "fall down, go down," from ob "down, away" (see ob-) + cadere "to fall" (see case (n.1)). The notion is of a "falling together," or juncture, of circumstances.
unemployed (adj.): 1600, "at leisure, not occupied," from un- (1) "not" + past participle of employ (v.). Meaning "temporarily out of work" is from 1660s. The noun meaning "unemployed persons collectively" is from 1782.
No man has hired us
With pocketed hands
And lowered faces
We stand about in open places
And shiver in unlit rooms ...

[T.S. Eliot, "Choruses from the Rock"]
unreal (adj.): c. 1600, "not real," from un- (1) "not" + real (adj.). Meaning "impractical, visionary" is by 1660s. Slang sense of "wonderful, great" is first recorded 1965.
Unreal City,
Under the brown fog of a winter dawn,
A crowd flowed over London Bridge, so many,
I had not thought death had undone so many.

[Eliot, "The Waste Land," 1922]
urn (n.): late 14c., "large, rounded vase used to preserve the ashes of the dead," from Latin urna "a jar, vessel of baked clay, water-jar; vessel for the ashes of the dead" (also used as a ballot box and for drawing lots), probably from earlier *urc-na, akin to urceus "pitcher, jug," and from the same source as Greek hyrke "earthen vessel." But another theory connects it to Latin urere "to burn" (compare bust (n.1)).
tar (n.2): also Jack Tar, "sailor," 1670s, probably a special use of tar (n.1), which stuff was a staple for waterproofing aboard old ships (sailors also being jocularly called knights of the tarbrush); or possibly a shortened form of tarpaulin, which was recorded as a nickname for a sailor in 1640s, from the tarpaulin garments they wore.
tassel (n.): c. 1300, "mantle fastener," from Old French tassel "tassel, fringe, hem; a fastening, clasp" (12c., Modern French tasseau), from Vulgar Latin *tassellus, said to be from Latin taxillus "small die or cube," a diminutive of talus "knucklebone (used as a die in gaming), ankle" (see talus (n.1)). But OED finds this doubtful and calls attention to the variant form tossel and suggests association with toss (v.). Meaning "hanging bunch of small cords" is first recorded late 14c.
undine (n.): female water spirit, 1821, from Modern Latin Undina (1650s), coined by Paracelsus ("De Nymphis") in his alchemical system, from Latin unda "a wave, billow" (see water (n.1)). Popularized by German romance "Undine, eine Erzählung" (1811) by Baron F.H.C. La Motte Fouqué. Undinism (1928) was coined by sex researcher Havelock Ellis to describe the fetish for urine (which Ellis had); nowadays it would be called urophilia.
rank (n.): early 14c., "row, line series;" c. 1400, a row of an army, from Old French renc, ranc "row, line" (Modern French rang), from Frankish *hring or some other Germanic source (compare Old High German hring "circle, ring"), from Proto-Germanic *hringaz "circle, ring, something curved" (see ring (n.1)).

Meaning "a social division, class of persons" is from early 15c. Meaning "high station in society" is from early 15c. Meaning "a relative position" is from c. 1600.
veil (n.): c. 1200, "nun's head covering," from Anglo-French and Old North French veil (12c., Modern French voile) "a head-covering," also "a sail, a curtain," from Latin vela, plural of velum "sail, curtain, covering," from PIE root *weg- (1) "to weave a web." Vela was mistaken in Vulgar Latin for a feminine singular noun. To take the veil "become a nun" is attested from early 14c.
venison (n.): c. 1300, from Old French venesoun "meat of large game," especially deer or boar, also "a hunt," from Latin venationem (nominative venatio) "a hunt, hunting, the chase," also "game as the product of the hunt," from venatus, past participle of venari "to hunt, pursue," probably from PIE *wen-a-, from root *wen- (1) "to strive for, desire" (see Venus).
vent (v.): late 14c., "emit from a confined space," probably a shortening of aventer "expose oneself to the air" (c. 1300), from Old French eventer "let out, expose to air," from Vulgar Latin *exventare, from Latin ex- "out" + ventus "wind" (see wind (n.1)). Sense of "express freely" first recorded 1590s. Sense of "divulge, publish" (1590s) is behind phrase vent one's spleen (see spleen). Related: Vented; venting.
racket (n.1): "loud noise," 1560s, perhaps imitative. Klein compares Gaelic racaid "noise." Meaning "dishonest activity" (1785) is perhaps from racquet, via notion of "game," reinforced by rack-rent "extortionate rent" (1590s), from rack (n.1). But it might as well be an extended sense of "loud noise" by way of "noise or disturbance made to distract a pick-pocket's victim."
railroad (n.): 1757, from rail (n.1) + road. Originally "road laid with rails for heavy wagons (in mining)." The process itself (but not the word) seems to have been in use by late 17c. Application to passenger and freight trains dates from 1825, though tending to be replaced in this sense in England by railway.
putty (n.): 1630s, "type of plasterer's cement," from French potée "polishing powder" (12c.), originally "pot-full, contents of a pot," from Old French pot "container" (see pot (n.1)). Meaning "soft mixture for sealing window panes" first recorded 1706. Figurative use in reference to one easily influenced is from 1924. Putty knife attested from 1834.
Pyrex (n.): 1915, proprietary name (Corning Glass Works, Corning, N.Y.), arbitrary coinage, in which eager etymologists see implications of Greek pyr "fire" and perhaps Latin rex "king;" but the prosaic inventors say it was based on pie (n.1), because pie dishes were among the first products made from it. The -r- is purely euphonious.
pajamas (n.): 1800, pai jamahs "loose trousers tied at the waist," worn by Muslims in India and adopted by Europeans there, especially for nightwear, from Hindi pajama, probably from Persian paejamah, literally "leg clothing," from pae "leg" (from PIE root *ped- (1) "foot," see foot (n.)) + jamah "clothing." Modern spelling (U.S.) is from 1845. British spelling tends toward pyjamas.
Gestalt (n.): 1922, from German Gestaltqualität (1890, introduced by German philosopher Christian von Ehrenfels, 1859-1932), from German gestalt "shape, form, figure, configuration, appearance," abstracted from ungestalt "deformity," noun use of adj. ungestalt "misshapen," from gestalt, obsolete past participle of stellen "to set, place, arrange" (see stall (n.1)). As a school of psychology, it was founded c. 1912 by M. Wertheimer, K. Koffka, W. Köhler.
junker (n.): "young German noble," 1550s, from German Junker, from Old High German juncherro, literally "young lord," from junc "young" (see young) + herro "lord" (see Herr). Pejorative sense of "reactionary younger member of the Prussian aristocracy" (1865) is from Bismarck's domestic policy. Related: Junkerism. Meaning "drug addict" is from 1922; that of "old worn-out automobile" is from 1969, both from junk (n.1).
cattle (n.): mid-13c., "property," from Anglo-French catel "property" (Old North French catel, Old French chatel), from Medieval Latin capitale "property, stock," noun use of neuter of Latin adjective capitalis "principal, chief" (see capital (n.1)). Compare sense development of fee, pecuniary. Sense originally was of movable property, especially livestock; it began to be limited to "cows and bulls" from late 16c.
demarcation (n.): c. 1752, from Spanish linea de demarcacion or Portuguese linha de demarcaçao, name of the line laid down by Pope Alexander VI, May 4, 1493, dividing the New World between Spain and Portugal on a line 100 leagues west of the Cape Verde Islands. Applied from 1801 to other lines dividing regions. From Spanish de- (see de-) + marcar "to mark the boundaries of," from a Germanic source (see mark (n.1)).
indignation (n.): c. 1200, from Old French indignacion "fury, rage; disrespect," or directly from Latin indignationem (nominative indignatio) "indignation, displeasure; a provocation, cause for indignation," noun of action from past participle stem of indignari "regard as unworthy, be angry or displeased at," from indignus "unworthy," from in- "not, opposite of" (see in- (1)) + dignus "worthy" (see dignity). The indignation meeting (1835) once was a common American way to express popular outrage by passing and publishing resolutions.
indiscreet (adj.): "imprudent, not discrete, lacking good judgment," early 15c., from Medieval Latin indiscretus, from in- "not, opposite of" (see in- (1)) + Latin discretus "separated, distinct" (in Medieval Latin "discerning, careful"), past participle of discernere "distinguish" (see discern). A Medieval Latin secondary sense of the word that also became indiscrete. Related: Indiscreetly; indiscreetness.