裤子 (kù zi) is a common Mandarin noun meaning 'pants' or 'trousers' — garments covering the lower body from waist to ankles, typically with two separate leg openings. The first character 裤 (kù) specifically denotes 'trousers' and carries the core meaning; the second character 子 (zi) is a neutral, grammatically light suffix often added to nouns to form colloquial, everyday terms (like 桌子 zhuōzi 'table', 瓶子 píngzi 'bottle'). Unlike English, Chinese rarely uses a bare form — 裤 alone is uncommon in speech; 裤子 is the standard, natural form used in daily conversation, shopping, and clothing descriptions.

This word applies to most types of pants worn by people of all ages and genders — jeans, dress trousers, sweatpants, and even children’s pants. It is not used for underwear (which is 内裤 nèikù) or shorts (短裤 duǎnkù). While formal writing may occasionally use 裤 without 子, learners should consistently use 裤子 in spoken and written communication to sound natural and avoid confusion.