英语词源字典 - 在线词源网站

unravel (v.)[unravel 词源字典]: c. 1600 (transitive), from un- (2) + ravel (v.). Intransitive from 1640s. "The prefix is either reversive or intensive, according as ravel is taken to mean 'tangle' or 'untangle'" [Century Dictionary]. Related: Unravelled; unravelling; unravellment.[unravel etymology, unravel origin, 英语词源]
unreachable (adj.): 1590s, from un- (1) "not" + reachable (adj.).
unread (adj.): mid-15c., from un- (1) "not" + past participle of read (v.).
unreadable (adj.): 1787, of written material, "dull, distasteful," from un- (1) "not" + readable (adj.). Meaning "illegible" is from 1830.
unready (adj.): mid-14c., "not prepared," from un- (1) "not" + ready (adj.).

In English history, applied from c. 1200 (Etheldredus Unrad) to Anglo-Saxon King Æðelræd II (968-1016), where it preserves Middle English unredi, a different adjective, from Old English ungeræd "ill-advised, rede-less, no-counsel" and plays on the king's name (which means "good-counsel"). Old English ræd "advice, counsel" is related to read (v.). Rede "counsel" survived in poetic usage to 17c. An attempted revival by Scott (19c.) failed, though it is used in Tolkien's "Lord of the Rings."
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]
unrealistic (adj.): 1865, from un- (1) "not" + realistic. Related: Unrealistically.
unreality (adj.): 1751, from un- (1) "not" + reality (n.).
unreason (n.): c. 1300, "injustice;" 1827, "absense of reason," from un- (1) "not" + reason (n.).
unreasonable (adj.): mid-14c., "irrational, illogical," from un- (1) "not" + reasonable. From late 14c. as "excessive, going beyond what is sensible or realistic." Related: Unreasonably; unreasonableness.
unrecognizable (adj.): 1817, from un- (1) "not" + recognizable (see recognize (v.)). Related: Unrecognizably.
unreconciled (adj.): mid-15c., from un- (1) "not" + past participle of reconcile (v.).
unreconstructed (adj.): 1867, "not reconciled to the outcome of the American Civil War," from un- (1) "not" + past participle of reconstruct (v.). See Reconstruction.
unredeemed (adj.): 1540s, "unsaved;" 1805, "not balanced by any good quality," from un- (1) "not" + past participle of redeem (v.).
unredorded (adj.): 1580s, from un- (1) "not" + past participle of record (v.).
unrefined (adj.): 1590s, "not refined in manners," from un- (1) "not" + past participle of refine (v.). Meaning "not free from gross matter" is recorded from 1610s.
unreformed (adj.): 1520s, from un- (1) "not" + past participle of reform (v.).
unregenerate (adj.): 1610s, from un- (1) "not" + regenerate (adj.).
unrelated (adj.): 1660s, "not akin," from un- (1) "not" + past participle of relate (v.). Meaning "not in any relationship" is attested from 1660s; that of "not told" is from 1764.
unrelenting (adj.): 1580s, from un- (1) "not" + present participle of relent (v.). Related: Unrelentingly.