- unfeasible (adj.)
- 1520s, from un- (1) "not" + feasible.
- unfeeling (adj.)
- late Old English, "having no sensation," from un- (1) "not" + feeling (see feel (v.)). Meaning "devoid of kindly or tender feelings" is recorded from 1590s. Related: Unfeelingly.
- unfeigned (adj.)
- late 14c., "sincere, genuine, true, real," from un- (1) "not" + past participle of feign.
- unfetter (v.)
- mid-14c., from un- (2) "opposite of" + fetter (v.). The figurative sense is recorded from late 14c. Related: Unfettered; unfettering.
- unfinished (adj.)
- 1550s, from un- (1) "not" + past participle of finish (v.).
- unfit (adj.)
- 1540s, "not suitable" (in reference to things), from un- (1) "not" + past participle of fit (see fit (adj.)). Related: Unfitness. In reference to persons or human qualities, attested from 1550s. The verb meaning "to render unfit" is recorded from 1610s.
- unflagging (adj.)
- 1715, from un- (1) "not" + present participle of flag (v.). Related: Unflaggingly.
- unflappable (adj.)
- 1958, from un- (1) "not" + flap (v.) + -able. Originally used in reference to Harold Macmillan, British P.M. 1957-63.
- unflattering (adj.)
- 1580s, from un- (1) "not" + gerundive of flatter. Related: Unflatteringly.
- unfledged (adj.)
- c.1600, of persons, "immature, not experienced," from un- (1) "not" + past participle of fledge. Literal sense of "not yet covered in feathers" is recorded from 1610s.
- unflinching (adj.)
- 1728, from un- (1) "not" + gerundive of flinch (v.). Related: Unflinchingly.
- unfold (v.)
- Old English unfealdan, "to open or unwrap the folds of," also figuratively, "to disclose, reveal," from un- (2) "opposite of" + fold (v.). Cf. Middle Dutch ontvouden, German entfalten. Intransitive sense is attested from late 14c. Related: Unfolded; unfolding.
- unforeseeable (adj.)
- 1670s, from un- (1) "not" + foreseeable (see foresee). Related: Unforeseeably.
- unforeseen (adj.)
- 1650s, from un- (1) "not" + past participle of foresee. Cf. Middle Dutch onvoresien, Dutch onvoorzien, Middle High German unvorsen.
- unforgettable (adj.)
- 1806, from un- (1) "not" + forgetable (see forget). Related: Unforgettably.
- unforgivable (adj.)
- 1540s, from un- (1) "not" + forgive + -able. In early use, especially with reference to the sin in Matt. xii:31. Related: Unforgivably.
- unforgiven (adj.)
- early 15c., from un- (1) "not" + past participle of forgive.
- unforgiving (adj.)
- 1713, from un- (1) "not" + present participle of forgive.
- unformed (adj.)
- early 14c., from un- (1) "not" + past participle of form (v.).
- unfortunate (adj.)
- 1520s, "unlucky," from un- (1) "not" + fortunate. Infortunate in same sense is from late 14c. (along with a verb infortune "to render unhappy," and a noun meaning "bad luck). In late 18c.-early 19c., unfortunate woman was a polite way to say "prostitute." The noun meaning "one who is not fortunate" is recorded from 1630s.
- unfortunately (adv.)
- 1540s, from unfortunate + -ly (2). Originally "not successfully, to a regrettable extent." The proper meaning is now rare; the main modern sense of "sad to say," in parenthetical use, recorded from 1770s.
- unfortune (n.)
- "misfortune," late 15c., from un- (1) "not" + fortune.
- unfounded
- 1640s, "having no foundation or basis," from un- (1) "not" + past participle of found (v.1).
- unfree (adj.)
- c.1300, from un- (1) "not" + free (adj.). Cf. Middle Dutch onvri, Old High German unfri, German unfrei, M.Da. ufri.
- unfrequented (adj.)
- 1580s, from un- (1) "not" + past participle of frequent (v.).
- unfriend (v.)
- in the Facebook sense, attested from November 2007, from un- (1) "not" + friend. Related: Unfriended; unfriending. A noun unfriend "enemy" is recorded from late 13c., chiefly in Scottish, and was still in use in the 19th century.
- unfriendly (adj.)
- early 15c., "not characteristic of friends," from un- (1) "not" + friendly. Cf. Middle Dutch onvriendelijc, Middle High German unvriuntlich, German unfreundlich. Meaning "hostile, inimical" is recorded from late 15c. Related: Unfriendliness.
- unfruitful (adj.)
- late 14c., "barren," from un- (1) "not" + fruitful. Originally literal; figurative sense is attested from c.1400. Related: Unfruitfully; unfruitfulness.
- unfulfilled (adj.)
- late 14c., from un- (1) "not" + past participle of fulfill.
- unfunny (adj.)
- 1858, from un- (1) "not" + funny.
- unfurl (v.)
- 1640s, from un- (2) "opposite of" + furl (v.). Related: unfurled, unfurling.
- unfurnished (adj.)
- 1540s, "not equipped, unprepared," from un- (1) "not" + past participle of furnish. In reference to houses, apartments, etc., "not provided with furniture," it is recorded from 1580s.
- ungainly (adj.)
- 1610s, originally "unfit, improper," from Middle English ungeinliche, from ungein (c.1400) "inconvenient" (from un- (1) "not" + Old Norse gegn "convenient") + -like.
- ungird (v.)
- Old English ongyrde, from un- (2) "opposite of" + gird. Cf. Middle Dutch ontgorden, Old High German ingurten, German entgürten. Related: Ungirded; ungirding.
- unglue (v.)
- 1540s, from un- (2) "opposite of" + glue (v.). Related: Unglued; ungluing. Unglued in figurative sense is recorded from 1922.
- ungodly (adj.)
- 1520s, "irreligious, not god-fearing, not in accordance with the laws of God," from un- (1) "not" + past participle of godly (adj.). Cf. Middle Dutch ongodelijc, German ungöttlich, Middle Swedish ogudhlik. Colloquial sense of "outrageous, dreadful" is recorded from 1887.
- ungracious (adj.)
- early 13c., from un- (1) "not" + gracious. Related: Ungraciously.
- ungrammatical (adj.)
- 1650s, from un- (1) "not" + grammatical. Related: Ungrammatically.
- ungrateful (adj.)
- 1550s, from un- (1) "not" + grateful. Related: Ungratefully.
- ungual (adj.)
- "pertaining to a nail or claw," 1834, from Latin unguis "a claw, nail" (cognate with Greek onyx, Old English nægel, Old Norse nagl "nail;" see nail (n.)).
- unguarded (adj.)
- 1590s, "not furnished with a guard," from un- (1) "not" + past participle of guard (v.). Sense of "not on one's guard, not taking heed" is attested from 1630s.
- unguent (n.)
- "ointment," mid-15c., from Latin unguentem "ointment," from stem of unguere "to anoint or smear with ointment," from PIE root *ongw- "to salve, anoint" (cf. Sanskrit anakti "anoints, smears," Armenian aucanem "I anoint," Old Prussian anctan "butter," Old High German ancho, German anke "butter," Old Irish imb, Welsh ymenyn "butter").
- ungulate (adj.)
- "hoofed," 1802, from Late Latin ungulatus "hoofed," from ungula "hoof, claw, talon," diminutive (in form but not sense) of unguis "nail" (see ungual). Ungulata, the order of hoofed mammals, is recorded from 1839.
- unh-unh
- sound expressing negation or denial, attested from 1951.
- unhallowed (adj.)
- Old English unhalgod, from un- (1) "not" + past participle of hallow.
- unhampered (adj.)
- 1690s, from un- (1) "not" + past participle of hamper (v.).
- unhand (v.)
- c.1600, "to release from one's grasp," from un- (2) + verbal derivative of hand (n.).
- unhappily (adv.)
- early 14c., from un- (2) + happily (see happy). Cf. Old Norse unheppiliga.
- unhappy (adj.)
- c.1300, "causing misfortune or trouble (to oneself or others)," from un- (1) "not" + happy. Meaning "unfortunate, unlucky" is recorded from late 14c.; sense of "miserable, wretched" is recorded from late 14c. (originally via misfortune or mishap).
- unharmed (adj.)
- mid-14c., from un- (1) "not" + past participle of harm.