noun
penalty drink; alcohol drunk as punishment
Refers to alcohol consumed as a penalty, typically in social drinking games or as a consequence for being late. Often used in the context of 罰ゲーム (punishment games).
See also: 罰杯
遅刻したので、罰酒を飲まされた。
I was made to drink a penalty drink because I was late.
ゲームに負けたら罰酒だよ。
If you lose the game, it's a penalty drink.