猜拳 is a traditional Chinese drinking game where two players simultaneously throw hand gestures (similar to rock-paper-scissors) and the loser must drink. It's a separable verb (离合词): the verb 猜 can be separated from the object 拳 by measure words, duration, or other elements — for example, 猜一次拳 ('play one round') or 猜了三拳 ('played three rounds'). You can also say 跟他猜拳 ('play the game with someone').