Swimsuit (yóuyǒng fú) is a compound noun formed from three characters: 游 (yóu, 'to swim'), 泳 (yǒng, also meaning 'to swim'—often used together with 游 as a disyllabic word for 'swimming'), and 服 (fú, 'clothing' or 'garment'). Though 游 and 泳 both mean 'swim', they combine here to specify the *purpose* of the clothing — for swimming. The third character, 服, clearly marks it as an item of apparel. This term is standard in modern Mandarin and used in everyday contexts like shopping, sports, and beach activities.

Unlike English, which has gendered terms like 'bikini' or 'trunks', 游泳服 is gender-neutral and covers all types of swimwear — one-piece suits, shorts, tankinis, and even competitive racing suits. It’s commonly seen on clothing labels, in department stores, and in fitness center announcements. While colloquial speech may use shorter forms like 泳衣 (yǒngyī), 游泳服 remains the most precise and widely understood formal term.