‘未尝’ is a literary adverb meaning ‘never’ or ‘not once’, used to emphasize that something has not occurred at all up to now. The first character 未 means ‘not yet’ or ‘not’, and 尝 originally means ‘to taste’ but here functions as a classical verb meaning ‘to experience’ or ‘to do’. Together, 未尝 literally conveys ‘has not experienced’, which evolved into the emphatic negative adverb ‘never’. It’s more formal and common in written Chinese, essays, speeches, or refined spoken contexts—not everyday casual speech.

This expression always appears before a verb or adjective and requires negation elsewhere only implicitly; it itself carries the negative meaning, so you don’t add 不 or 没 before it. It often pairs with modal verbs like 可, 能, or 会 to express possibility or willingness (e.g., 未尝不可 — ‘not impossible’). While grammatically similar to 没有 or 从未, 未尝 adds a subtle tone of reflection, nuance, or rhetorical elegance.