swinger
noun [ C ] old-fashioned slang uk/ˈswɪŋ.ər/ us/ˈswɪŋ.ɚ/
时髦的人，放荡的人;性滥交的人
a person who dresses in a fashionable way and who goes to a lot of parties and nightclubs, or someone who is willing to have sex often with many different people