Your kicks are so powerful you use them to push or knock back your foes.
Benefit: You must declare that you are using this feat before you make your attack roll (thus a failed attack roll ruins the attempt). On a successful hit, the attack deals damage normally and you can choose to push your target 5 feet or attempt to knock them prone. If you decide to push the target, it is moved 5 feet directly away from you. This movement does not provoke attacks of opportunity, and the target must end this move in a safe space it can stand in. If you decide to attempt to knock the target prone, the target receives a Fortitude saving throw with a DC of 10 + 1/2 your character level + your Wisdom modifier to avoid the effect. You may attempt a punishing kick attack once per day for every four levels you have attained (but see Special), and no more than once per round.
Special: A hungry ghost monk receives Punishing Kick as a bonus feat at 1st level, even if he does not meet the Prerequisites. A monk may attempt a punishing kick attack a number of times per day equal to his monk level, plus one more time per day for every four levels he has in classes other than monk.
Advanced Player’s Guide. Copyright 2010, Paizo Publishing, LLC; Author: Jason Bulmahn.