不够 means 'not enough' or 'insufficient' for quantities, degree, or requirements. It is the negative form of 够 (gòu) and is more everyday than the formal/literary 不足 (bùzú). Unlike 缺少 (quēshǎo), which indicates a lack of a specific item, 不够 focuses on the amount or level not meeting a standard; it can also be used as an adverb before adjectives (e.g., 不够好 'not good enough').