CEDICT
to play a game in which the participant guesses the figures the opponent will express with fingers, often as a drinking game
Wiktionary
猜拳,以手出数目决定胜负,饮酒时常以此助兴。
重編國語辭典
以手出数目决定胜负,饮酒时常以此助兴
維基詞典