不得不 bùdébù HSK3 have to Origin Definitions Defs Strokes Stroke Words Sentences Sents 不得 bùdé verb cannot cannot; to be unable to; often used in set phrases like 不得而知 bùdé'érzhī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