Playing to a level that is far above what the other players are doing. Using strategies that are not fathomed by 99% of the general public. Generally used in poker but can reach to other games such as scrabble, golf, and guitar hero. You must be careful when playing above the rim (ATR) because 'when you are above the rim, everyone can see you'.
"Wow, wow, did you really minraise that with just middle pair, that was so above the rim."
"Yea, Mike Rizz will be here later. Be carefull in pots against him, he plays above the rim"