1 definition by COOLMASTER X

1)someone who doesn't want others to enjoy something because it is in his/her taste.

2) someone who doesn't like happiness, laughter or fun especially when the person is not involved/invited and comes in to ruin it.
1) James is always coming in and cutting off the game because he sucks at it, he is such a killjoy.

2) Whenever we are laughing, joking or playing a fun game, it bugs jim's father so much that he runs downstairs and ruins it for us. tsk, tsk...such a killjoy.
by COOLMASTER X October 15, 2009
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