1 definition by ErrorFM

Someone who either directly or indirectly prevents people from having fun.
Roommate 1: Hey man, it's raining, can we smoke in the dorm?

Roommate 2: No, Roommate 3 is being a prune and is spending all day in the dorm, and he'll totally rat on us if we smoked while he was in the room.

Roommate 1: Fuck man, prunes ruin everything.
by ErrorFM February 5, 2010
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