tranquilizer (n.)youdaoicibaDictgodict[tranquilizer 词源字典]
1800, "that which tranquilizes;" from 1824 as "a sedative" (first reference is to ground ivy), agent noun from tranquilize; in reference to one of a large group of anti-anxiety drugs, it is recorded by 1956.[tranquilizer etymology, tranquilizer origin, 英语词源]