不易
búyì · HSK 5
uneasy
不 = not + 易 = easy → not easy, uneasy
不 negates and 易 means easy or change. Together they spell out not-easy, which carries over directly to the English uneasy or difficult.
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'.