fast and looseyoudaoicibaDictYouDict[fast and loose 词源字典]
described as "a cheating game played with a stick and a belt or string, so arranged that a spectator would think he could make the latter fast by placing a stick through its intricate folds, whereas the operator could detach it at once." [James O. Halliwell, "Dictionary of Archaic and Provincial Words," 1847]. The figurative sense (1550s) is recorded earlier than the literal (1570s).[fast and loose etymology, fast and loose origin, 英语词源]