不曾
bù céng · HSK 5
hasn't ever
不 (not) + 曾 (ever/once) = has not ever
不 negates; 曾 (céng) means once/formerly/ever. Together: never has, hasn't yet. Compare 曾经 céngjīng (formerly) — same 曾 carries the past-experience sense.
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'.
曾 — top 八 + 田-like body + 日 (steamer pictograph)
曾 originally pictured a tiered bamboo steamer with rising vapor, the ancestor of 甑 'steamer pot.' It was borrowed phonetically for the grammatical meanings 'once, formerly' (zēng) and 'great-grand-' in kinship terms. Later 甑 was created with the 瓦 'tile/pottery' radical to keep the original cooking-vessel sense.