忍不住
rěnbúzhù · HSK 5
can't help but do something
🙈 忍不住 = endure + not + hold = can't hold back from doing it
忍 (endure) + 不 (not) + 住 (hold/stop). Literally 'endure-not-stop' — the endurance won't hold, so the action leaks out. Used for laughing, crying, or blurting things you meant to suppress.
忍 — blade 刃 (phonetic) + heart 心 (semantic)
忍 is a semantic-phonetic compound: 心 'heart' below gives the meaning, while 刃 'blade' above provides the sound. The image of a blade over the heart vividly suggests enduring pain or restraining oneself, hence the meanings 'endure, bear, be patient'.
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'.
住 — person radical 亻 + 主 (master/zhǔ, phonetic)
住 is a semantic-phonetic compound. The left side 亻 (person) gives the meaning—something a person does—while 主 supplies the sound, originally 'zhǔ' (master, a lamp standing in place). Together they suggest a person staying put, yielding the senses 'to live, dwell, reside, stop'.