1 (also il- /ɪl ||; ɪl/im- /ɪm ||; ɪm/ir- /ɪr ||; ɪr/) (in adjectives, adverbs and nouns) not; the opposite of （用于构成形容词、副词及名词）不，非，相反: infinite 无限的illogical 不合逻辑的immorally 不道德irrelevance 不相干

2 (also im- /ɪm ||; ɪm/) (in verbs 用于构成动词) to put into the condition mentioned 放在…里；使陷于…: inflame 使燃烧imperil 使陷于危险