没用 (méi yòng) is an adjective meaning 'useless' or 'of no use'. It literally combines 没 (méi), meaning 'not have' or 'not', and 用 (yòng), meaning 'use' or 'utility'. Together, they express the absence of practical value or function. Unlike many adjectives in Chinese, 没用 does not require the particle 得 (de) to form complements and is often used predicatively — that is, after a subject and before a pause or sentence end.

This word carries a mildly negative or dismissive tone and is common in everyday speech when evaluating tools, ideas, people’s efforts, or even one’s own abilities. It can sometimes sound blunt or discouraging, especially when directed at people ('你真没用' — 'You’re really useless'), so context and tone matter greatly. It’s frequently used in informal settings but avoided in formal writing or polite feedback.