背心 (bèi xīn) means “sleeveless garment (vest, waistcoat, singlet, tank top etc)”. It is an HSK 6 Chinese word in the HSK 3.0 vocabulary.
Measure word: 件
Practice each character:
夏天穿背心比较凉快。
Xiàtiān chuān bèi xīn bǐjiào liángkuai.
Wearing a vest in summer is cooler.
Updated: 2026-07-18