Someone who claims to be a fan of "Role Playing Games" (usually limited to the pen and paper and even more so massively multiplayer online variety) but whom does very little actual "roleplaying". Instead they tend to concentrate more on building the most obscenely powerful character possible, anyway possible, even at the expense of other players fun.
If you are looking for a good massively multiplayer online role playing game I suggest you choose one with a strong roleplaying community, not a rollplaying one.
Player-A cares more about his character than he does about others playing the game. What a rollplayer!