A gamer who learnes the rules of a game inside and out to perfection in order to become the best at that game. In games such as D&D
a power gamer might sacrifice role-playing
in favor of more power for his character, although most do not. Power gamers often make the game less fun for the rest of the playing group for the reason that their characters usually become far more powerful then all other characters in play.
Power gamers are often wrongly known as munchkins. A munchkin
gains power by cheating while a power gamer gains power by knowing and using the rules of the game to his advantage.
Wow, that damn power gamer's character is way too strong for his level. That's just not fair.