英语词源字典 - 在线词源网站

unbecoming (adj.)[unbecoming 词源字典]: 1590s, from un- (1) "not" + becoming "fitting." Related: Unbecomingly.[unbecoming etymology, unbecoming origin, 英语词源]
unbefitting (adj.): 1580s, from un- (1) "not" + befitting.
unbefriended (adj.): from un- (1) "not" + past participle of befriend (v.).
unbegotten (adj.): 1530s, from un- (1) "not" + begotten.
unbegun (adj.): Old English unbegunnen; see un- (1) "not" + begun.
unbeknown (adj.): "unknown," 1630s, from un- (1) "not" + beknown (see beknow).
unbeknownst (adj.): 1833, vulgar formation from unbeknown (1630s). No clear reason for the -st, but since 19c. this has become the dominant form.
unbelief (n.): mid-12c., "absence or lack of religious belief; disbelief of the truth of the Gospel," from un- (1) "not" or un- (2) "opposite of" + belief. Old English had ungeleafa in this sense.
unbelievable (adj.): 1540s, from un- (1) "not" + believable. Related: Unbelievably.
unbeliever (n.): "one who does not believe in any given religion," 1520s, from un- (1) "not" believer. Old English had ungelifend in this sense.
unbend (v.): mid-13c., "relax a bow by unstringing it," from un- (2) "reverse, opposite of" + bend (v.). Intransitive sense from 1746. Figurative meaning "to become genial, relax" (1748) has a sense opposite to that of unbending "inflexible, obstinate" (1680s), which does not derive from the bow-stringing image.
unbeseeming (adj.): 1580s, "not befitting, inappropriate, unsuitable," from un- (1) "not" + beseeming. A common 17c. word.
unbesought (adj.): 1660s, from un- (1) "not" + besought.
unbias (v.): "to free from bias," 1708, from un- (2) "reverse, opposite of" + bias (v.).
The truest service a private man may hope to do his country is, by unbiassing his mind as much as possible. [Swift, "The Sentiments of a Church of England Man with respect to Religion and Government," 1708]
unbiased (adj.): c. 1600, literal, in reference to throws at bowls, from un- (1) "not" + biased. Figurative sense of "impartial, unprejudiced" is recorded from 1640s.
unbidden (adj.): Old English unbedene, "not asked or invited," from un- (1) "not" + bidden. Similar formation in Middle Dutch ongebeden, German ungebeten, Old Norse ubeðinn.
unbind (v.): Old English unbindan, "to free from binding," from un- (2) "opposite of, reverse" + bind (v.). Similar formation in Old Frisian unbinda, German entbinden, Dutch ontbinden. Literal and figurative senses both present in Old English.
Suæ huæt ðu unbindes ofer eorðu bið unbunden in heofnum. [Lindisfarne Gospels, Matt. xvi:19]
Unbound is from Old English unbunden, in literal sense. Figurative sense first attested late 14c.; of books from 1540s.
unbleached (adj.): 1530s, from un- (1) "not" + past participle of bleach (v.).
unblemished (adj.): c. 1300, from un- (1) "not" + past participle of blemish (v.). Originally in moral sense; material sense is attested from mid-15c.
unblown (adj.): "not yet bloomed," 1580s, from un- (1) "not" + past participle of blow (v.2).
Life is the rose's hope while yet unblown;
The reading of an ever-changing tale;

[Keats, "Sleep and Poetry"]