不懈
bù xiè · HSK 7
untiring
💪🔥 bù xiè = not + slack off — literally never letting up
不 means not, 懈 means to slacken or relax effort. Together they describe someone who refuses to ease up — relentless, persistent, never coasting.
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'.