二百五十 (èr bǎi wǔ shí) literally means 'two hundred fifty', but it is widely used as a slang insult in Chinese, equivalent to calling someone an 'idiot' or 'fool'. The origin is folk-etymological: in old Beijing, a person who sold for 250 cash was considered foolish. As a noun, it refers to a stupid or clueless person. Be careful — it is offensive and not used lightly, though among close friends it can be teasing. The literal numeric meaning is also valid in contexts like prices or counting, but the slang sense is the primary cultural reference.