A rules lawyer is a term used to describe a participant in a rules-based environment who attempts to use the letter of the law without reference to the spirit, usually in order to gain an advantage within that environment.
[1] The term is commonly used in wargaming and tabletop role-playing game communities,[2] often pejoratively, as the "rules lawyer" is seen as an impediment to moving the game forward.
[3] The habit of players to argue in a legal fashion over rule implementation was noted early on in the history of Dungeons & Dragons.
[4][5] Rules lawyers are one of the "player styles" covered in Dungeon Master for Dummies.
[6] The rules of the game Munchkin include various parodies of rules lawyer behavior.