前綴 un-

漢： 前綴un-來(lái)源于盎格魯-撒克遜語(yǔ)，在形容度詞或副詞前，意為“not”；在名詞前，意為“lack of reverse of”。此外，用做“cause to be no longer degrade from the position of”等意思時(shí)，主要把名詞轉(zhuǎn)為動(dòng)詞，或表示與原動(dòng)詞意思相對(duì)或相反的行為。

英：
un- (1)
prefix of negation, Old English un-, from P.Gmc. *un- (cf. Old Frisian, Old High German, German un-, Gothic un-, Dutch on-), from PIE *n- (cf. Sanskrit a-, an- "not," Greek a-, an-, Old Irish an-, Latin in-), a variant of PIE root *ne- "not" (cf. Avestan na, Old Church Slavonic and Lithuanian ne "not," Latin ne "that not," Greek ne- "not," Old Irish ni, Cornish ny "not").

Freely and widely used since Old English in compounds with native and imported words, it disputes with Latin-derived cognate in- the right to form the negation of certain words (indigestable/undigestable, etc.). Often euphemistic (e.g. untruth for "lie"). The most prolific of English prefixes, it even is used to make words from phrases (e.g. uncalled-for, c.1600; undreamed-of, 1630s; uncome-at-able, 1690s; unputdownable, 1947, of a book; un-in-one-breath-utterable, Ben Jonson; etc.). As a prefix in telegram-ese to replace not and save the cost of a word, it is first attested 1936.
un- (2)
prefix of reversal (e.g. unhand, undo, unbutton), O.E. on-, un-, from P.Gmc. *andi- (cf. O.S. ant-, O.N. and-, Du. ont-, O.H.G. ant-, Ger. ant-, Goth. and- "against"), from PIE *anti "facing opposite, near, in front of, before" (see ante).

共詳細(xì)分為以下六類意思：
1.un-表示“不”
unabashed
a.not abashed,embarrassed or awed 不害怕的，不難為情，泰然的
Tim appeared unabashed by all the media attention
蒂姆成了媒體的焦點(diǎn)，卻也滿不在乎。

unalterable
a.not alterable 無(wú)法變更的 alter=other
The state of New York has designed its new drivers'licenses to be virtually.
紐約新設(shè)計(jì)的駕駛執(zhí)照實(shí)際上是不可變更的。

2.un-表示“無(wú)”
uncouth
a.tough,awkward,not cultured (人，行為)粗魯?shù)?，粗俗的；笨拙的；無(wú)教養(yǎng)的
A man considered uncouth or mean; a boor.
被認(rèn)為粗魯?shù)幕虮氨傻娜? 舉止粗魯?shù)娜?/p>

3.un-表示“非”
unearthly
a.very strange;superntural and therefore frightening 非自然的；異常的；怪異的；
An unearthly glow emanated from the house.
那個(gè)房子里發(fā)出一束奇異的光。

4.un-表示“未”
unmitigated
a.not mitigated;complete;absolute 未減輕的；完全的；絕對(duì)的 詞根mitig=soft
The UN can no longer turn a blind eye to the unmitigated suffering of the Bosnians.
聯(lián)合國(guó)再也不能對(duì)波斯尼亞人未曾減輕的痛苦坐視不管了。

5.un-表示“相反動(dòng)作、取消、除去”
unlock
vt. 開(kāi)啟，顯露，放開(kāi)
I unlocked the door and went into the room.
我打開(kāi)房門(mén)，然后走進(jìn)屋里。

6.un-表示“由...中弄出”
untomb
v. 由墳?zāi)怪芯虺?，揭?/p>

unearth
vt. 發(fā)掘，掘出，發(fā)現(xiàn)并披露
I unearthed the portrait from the attic.
我從閣樓上搜出這幅畫(huà)像。