英语否定前缀

How are these prefix(un-, in-(ir-,il-,im-), non-, dis-, a-,etc. )different in actual usage?

un-1
1(added to adjectives, participles, and their derivatives) denoting the absence of a quality or state; not
用于形容词、分词及其派生词前］表示“否”，“非”
unabashed.不害臊的; 公然的
unacademic.
unrepeatable.

2 the reverse of (usually with an implication of approval or disapproval, or with another special connotation).
表示“相反”，“对立”
unselfish.
unprepossessing.不吸引人的,不妩媚的
unworldly.不谙世故的, 不善于处世的

3 (added to nouns) a lack of [用于名词前］表示“缺少”
unrest.动乱, 骚乱, 不安宁
untruth.谎言

un-2
4 added to verbs 动词前缀 denoting the reversal or cancellation of an action or state 表示“做相反的动作”或“取消”
untie.松开, 解开
unsettle.扰乱, 使不安宁
5 denoting deprivation, separation, or reduction to a lesser state 表示“免去”，“剥夺”，“使降级”
unmask.除去(某人的)面具;使(某人或某事)露出真相; 揭露
unman.使失去男子气质,阉割,使怯懦,使气馁
6 denoting release. 表示“除去”，“使自由”
unburden.卸去负荷;吐露心事, 消除(思想、心灵上的)负担
unhand.将…放掉,把手从…移开


in-1
1(added to adjectives) not 形容词前］表示"不"
infertile.不能生育的;贫瘠的
inapt.不恰当的;不熟练的
2(added to nouns) without; a lack of 加在名词前］表示"无"，"缺"
inappreciation.不欣赏,不正确评价

in-2
3 in; into; towards; within 表示"在里"，"入内"，"朝"，"内"
induce.引诱, 劝导
influx.大量涌入
inborn.天生的, 先天的, 固有的
*用法:In- is also found assimilated in the following forms: il- before l; im- before b, m, p; ir- before r.
e.g. illegal; imbalance; immature; impatient; irreconcilable


non-
1 not doing; not involved with 表示“不”，“非”
non-aggression.不侵犯,不侵略
non-recognition.不承认
2 not of the kind or class described 表示“非”
non-believer.没有信仰的人,不信上帝的人
nonconformist.不信奉英国国教的新教教徒;不墨守成规者
also forming nouns used attributively (such as non-union in non-union miners).
［也构成用作修饰语的名词］表示“非”（如non-union miners中的non-union)
3 not of the importance implied 表示“不重要的”
non-issue.不成问题的问题
a lack of 表示“无”
non-aggression.
4 (added to adverbs) not in the way described［与副词组合］表示“非”
non-uniformly.不一致地,不均匀地
5 (added to verbs to form adjectives) not causing or requiring［与动词组合构成形容词］表示“不致”；“无需”
non-skid.防滑的,不滑的
non-iron.(洗后)免熨的
expressing a neutral negative sense when a corresponding form beginning with in- or un- has a special connotation

(such as non-human

compared with inhuman)
［当相应的以in-或un-开头的否定形式带有特殊含义时，用以表示中性否定］表示“非”（如non-human非人类的，不属于人类的，比较inhuman无人性的；冷漠的)

*用法:
The prefixes un- and non- both mean ‘not’, but there is often a distinction in terms of emphasis. un- tends to be

stronger and less neutral than non-: consider the differences between unacademic(非学术上的/（人）不适合做学术的)

and non-academic(非学术类), for examplehis language was refreshingly unacademic; a non-academic life suits him.


dis-
1 expressing negation 表示“否定”
disadvantage.
2 denoting reversal or absence of an action or state 表示“相反”，“缺乏”
diseconomy.
disaffirm.
3 denoting removal of something 表示“去除”
disbud.摘去嫩芽
disafforest.砍伐森林
4 denoting separation. 表示“分离”
discarnate.无形的,脱离肉体的
5 denoting expulsion. 表示“逐出”
disbar.取消律师出庭的资格
6 expressing completeness or intensification of an unpleasant or unattractive action 表示“完全地”
disgruntled.不满的, 不高兴的


a-1
not; without 表示“不”，“没有”
atheistic.无神论的,无神论者的
acephalous.无头的,群龙无首的
*assimilated before sc, sp, and st (as in ascend, aspire and astringent). variant spelling of ad- 同 ad- （ad在sc, sp和st前同化为a，如aspire和astringent）