slang Someone who engages in promiscuous sexual activities, especially while married to or in a committed relationship with another person who accepts or participates in such sexual activities as well. We've been experimenting with swingers from all over town for the past 10 years, and it has only ever made our own marriage stronger. He said that he and his wife were swingers and wanted me to join in with them, but I told them I wasn't into that sort of thing.