Definitions for "Griefer"
Keywords:  pvp, harass, gamers, multiplayer, annoy
A character who commits acts for no reason other than to upset the game. Such actions usually include a blatant disregard for the rules. Griefers will not be tolerated, and may not receive a warning before being removed from the game. HP – Hit points. The amount of physical punishment a character or monster can take.
A player who tries to spoil the fun of other players by harassing them. This behaviour is disapproved of by on-line gamers, and consequently griefer is a term of abuse.
a player bent on purposely frustrating others during a multiplayer game
inexistent word very commonly used at MMOG to refer to Griever
Similar to a ganker, this kind of person makes your playing experience unenjoyable.