non-
/nɒn/prefix
1
- not doing; not involved with表示“不”, “非”：
non-aggression
non-recognition.
2
- not of the kind or class described表示“非”：
non-believer
nonconformist.
2.1
- 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.
4
- a lack of表示“无”：
non-aggression.
5
- (added to adverbs) not in the way described与副词组合表示“非”：
non-uniformly.
6
- (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
non-iron.
7
- 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, 比较inhuman）。
USAGE
The prefixes non- and un- both have the meaning 'not', but tend to be used with a difference of emphasis. See usage at UN-1.
词源
from Latin non 'not'.