不可不 bùkěbù must Origin Definitions Defs Strokes Stroke Words Sentences Sents 不可 bùkě auxiliary [necessity] Used in the 非...不可 fēi... bùkě pattern to indicate that something must be done or is unavoidable.不 bù adverb not Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings