不得不
bùdébù · HSK 3
have to
不得 = cannot + 不 = not; 'cannot-not' = have no choice but to
Double negative built from 不 (not) + 得 (get/can) + 不 (not). Literally 'not-able-not', i.e. 'cannot not do it' — forced into the action. The repeated 不 brackets 得 to lock in the no-way-out meaning.
不 — single pictograph; bird flying upward
Originally a pictograph in oracle bone script, traditionally interpreted as a bird flying up toward the sky and unable to come down, suggesting negation or refusal. Over time it became the standard negation word in Chinese, used before verbs and adjectives to mean 'not'.
得 — 彳 (step) + 旦 (sun/day) + 寸 (hand)
Originally depicted a hand 寸 reaching for a cowrie shell 貝 (later simplified to 旦), with 彳 'step' added to show going out and obtaining something. The core meaning is 'to get' or 'obtain'. The reading děi extends this to 'must/have to' — what one is obliged to get done.
不 — single pictograph; bird flying upward
Originally a pictograph in oracle bone script, traditionally interpreted as a bird flying up toward the sky and unable to come down, suggesting negation or refusal. Over time it became the standard negation word in Chinese, used before verbs and adjectives to mean 'not'.