Used in online games to describe a player that thinks they are a pro, but in reality they are just a fag. Mainly for First person shooter games, all players that whinge every time they are killed, if they lag, if they think someone is hacking but they aren't, etc.
<CLAN>Profag: BS I SHOT YOU
Good player: you hit me once.
(Profag gets killed again)
<CLAN>Profag:FUCKING LAG this host is shit
Good player:clearly a Profag.