1. Somebody who always looks on the dark side, thinks negatively, and assumes what can go wrong should go wrong.

2. A person who replies to statements, and situations ignoring anything good that happened and only points out the bad things
(Definition 1, Tom being the pessimaster)
Tom: Somebody's gonna come to school with a gun and shoot us
Craig: That's not gonna happen, man don't think like that

Tom: Dude you know there are crazy people in the school, someone will start shooting one day

(Definition 2, Craig being the pessimaster)

Tom: The running back just got like 40 yards on the play

Craig: But he didn't get a touchdown

Tom: He still got a big gain, and it was a sweet run

Craig: But somebody tackled him and stopped the play, so it wasn't that sweet
by Optical Epilepsy September 9, 2009
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