1. The term used to give a large quantity of alcohol. A "Fucked Up" shot of alcohol.
2. A shot of alcohol served by a ninja with kung fu skills. If a consumer of alcohol finishes their shot the said ninja can replace the shot without the consumers knowledge thus forcing the consumer to question if they really did finish their previous shot.
Girl: how much have you put in there?
Dude: there's a Fu shot
Party host: FU shots all round