Meta game[ing] is when you played it for a very, very long time and basically know everything about that game, literary knowing everything about that game, every detail, just everything. However, you know so much it's almost like you are the maker of the things in that game, and you take the game quite seriously. You are a cunning and strong fighter, and almost can predict your opponents' moves. You know every secret and simply everything in it. You are a master at that game. That's what meta gaming is. Hope it helps!