A task or activity that is foolish, dangerous, or will not result in a positive outcome. Primarily heard in UK. Allowing your children to play with fireworks is a mug's game. They are bound to get injured.
1. n. the face. (Crude.) Wipe that smile off your mug!
2. n. a thug; a goon. (Underworld.) Call off your mugs. I’ll come peacefully.
3. tv. to attack and rob someone. Somebody jumped out of an alley and tried to mug me.
mug shot
n. a photograph of one’s face taken for police records. (Underworld.) I’m going to have to ask you to come down to the station and go through some mug shots.