vest /vest/ n. ［c］ 汗衫，背心，马甲：a cotton vest 棉织背心；a running vest跑步用背心；a bulletproof vest防弹背心She was dressed only in a vest and underpants.她只穿了一件汗衫和一条短裤。You'd better wear a vest under a coat.你最好把马甲穿在上衣里面。