Griefing
The term "griefing" became popular with the proliferation of MMORPG's. Griefing is a term used to describe players whos sole intentions are to cause grief for other players. Griefer's usually participate in the theft of items from other online characters, unwarranted and unbiased player-killing, and even deception. Griefer's are a pain to the majority of players in a community as well as to the developers of a particular game. Griefers usually stay within the bounds and guidelines of the game, therefore they cause a miserable experience for other players, yet can't be disciplined by developers due to their abidance to the rules.