- unmet (adj.)
- c. 1600, from un- (1) "not" + past participle of meet (v.).
- unmindful (adj.)
- late 14c., from un- (1) "not" + mindful (adj.).
- unmistakable (adj.)
- 1660s, from un- (1) "not" + mistake (v.) + -able. Related: Unmistakably.
- unmitigated (adj.)
- 1590s, from un- (1) "not" + past participle of mitigate (v.).
- unmodified (adj.)
- 1792, from un- (1) "not" + past participle of modify (v.).
- unmolested (adj.)
- 1530s, from un- (1) "not" + past participle of molest (v.).
- unmoor (v.)
- late 15c., "to free from moorings," from un- (2) "reverse, opposite of" + moor (v.). Related: Unmoored.
- unmotivated (adj.)
- "lacking in motivation," by 1917, from un- (1) "not" + past participle of motivate. Meaning "lacking in motive" is attested from 1871. Unmotived is from 1794.
- unmounted (adj.)
- 1590s, from un- (1) "not" + past participle of mount (v.).
- unmovable (adj.)
- late 14c., from un- (1) "not" + movable (adj.).
- unmoved (adj.)
- late 14c., "not affected by emotion or excitement," from un- (1) "not" + past participle of move (v.). Meaning "fixed in position" is from mid-15c.
- unmuzzled (adj.)
- c. 1600, from un- (1) "not" + past participle of muzzle (v.), or past participle of unmuzzle (v.), which is attested from c. 1600.
- unnamed (adj.)
- c. 1500, "not mentioned by name." from un- (1) "not" + past participle of name (v.). Similar formation in Old Frisian unnamed, Middle Dutch ongenaemt.
- unnatural (adj.)
- early 15c., "not in accord with physical nature," from un- (1) "not" + natural (adj.). Meaning "artificial" is attested from 1746; that of "at variance with moral standards" is from 1520s. Related: Unnaturally; unnaturalness.
- unnecessary (adj.)
- 1540s, from un- (1) "not" + necessary (adj.). Related: Unnecessarily.
- unneeded (adj.)
- 1725, from un- (1) "not" + past participle of need (v.).
- unnerve (v.)
- 1620s, "to destroy the strength of," from un- (2) "reverse, opposite of" + nerve (v.). Meaning "to deprive of courage" is recorded from 1704. Related: Unnerved; unnerving.
- unnoticed (adj.)
- 1720, from un- (1) "not" + past participle of notice (v.).
- unnumbered (adj.)
- late 14c., from un- (1) "not" + past participle of number (v.).
- unobjectionable (adj.)
- 1793, from un- (1) "not" + objectionable (adj.).
- unobservant (adj.)
- 1660s, from un- (1) "not" + observant (adj.).
- unobserved (adj.)
- 1610s, from un- (1) "not" + past participle of observe (v.).
- unobstructed (adj.)
- 1650s, from un- (1) "not" + past participle of obstruct (v.).
- unobtainable (adj.)
- 1775, from un- (1) "not" + obtainable (adj.). Related: Unobtainability.
- unobtrusive (adj.)
- from un- (1) + obtrusive (adj.). Related: Unobtrusively; unobtrusiveness.
- unoccupied (adj.)
- late 14c., "idle," from un- (1) "not" + past participle of occupy (v.). In reference to ground, etc., "not possessed, not made use of," from early 15c.
- unoffending (adj.)
- 1560s, from un- (1) "not" + present participle of offend (v.).
- unofficial (adj.)
- 1798, from un- (1) "not" + official (adj.). Related: Unofficially.
- unopposed (adj.)
- 1650s, from un- (1) "not" + past participle of oppose (v.).
- unorganized (adj.)
- 1680s, from un- (1) "not" + past participle of organize (v.).
- unoriginal (adj.)
- 1660s, "uncreated, without an origin," from un- (1) "not" + original (adj.). Meaning "derivative, second-hand" is recorded from 1774. Related: Unoriginality.
- unorthodox (adj.)
- 1650s, from un- (1) "not" + orthodox (adj.).
- unorthodoxy (n.)
- 1704, from unorthodox + -y (4).
- unostentatious (adj.)
- 1747, from un- (1) "not" + ostentatious (adj.). Related: Unostentatiously.
- unowned (adj.)
- 1610s, "unpossessed," from un- (1) "not" + past participle of own (v.). From 1715 as "unacknowledged."
- unpack (v.)
- late 15c., from un- (2) "reverse, opposite of" + pack (v.). Similar formation in Dutch ontpakken. Related: Unpacked; unpacking.
- unpaid (adj.)
- late 14c., in reference to persons, from un- (1) "not" + past participle of pay (v.). Of debts, attested from late 15c.
- unpalatable (adj.)
- 1680s, from un- (1) "not" + palatable (adj.). Related: Unpalatably.
- unparalleled (adj.)
- 1590s, from un- (1) "not" + past participle of parallel (v.). Unparallel as an adjective is recorded from 1650s.
- unpardonable (adj.)
- 1520s, from un- (1) "not" + pardonable (adj.). Related: Unpardonably. Impardonable also is from 1520s.
- unpatriotic (adj.)
- 1775, from un- (1) "not" + patriotic.
- unpaved (adj.)
- 1530s, from un- (1) "not" + past participle of pave (v.).
- unpenetrable (adj.)
- c. 1400, from un- (1) "not" + penetrable (adj.). The usual word now is impenetrable.
- unperceived (adj.)
- mid-14c., from un- (1) "not" + past participle of perceive (v.).
- unpersuasive (adj.)
- 1748, from un- (1) "not" + persuasive (adj.). Related: Unpersuasively.
- unperturbed (adj.)
- early 15c., from un- (1) "not" + past participle of perturb (v.).
- unplace (v.)
- from un- (2) "reverse, opposite of" + place (v.). Related: Unplaced; unplacing.
- unplanned (adj.)
- by 1804, from un- (1) "not" + past participle of plan (v.).
- unpleasant (adj.)
- 1530s, from un- (1) "not" + pleasant (adj.). Related: Unpleasantly.
- unpleasantness (n.)
- 1540s, "state or quality of being unpleasant," from unpleasant + -ness. By 1835 as "a slight quarrel, a minor misunderstanding." The late unpleasantness as a humorously polite Southern description of the American Civil War is attested from 1868.
