1550s, "moving to and fro," present participle adjective from swing (v.). Meaning "marked by a free, sweeping movement" is from 1818. Sense of "uninhibited" is from 1958.
例文
1. The stuffy "50 s gave way to the swinging "60 s.
古くさい50年代は多彩な60年代に取って代わられた。
2.He slides the bolt in place to keep the door from swinging .