'Spoiling' refers to the art of punching the ball away from an opponent who is attempting to take a mark.
It's an important defensive skill that should be mastered by all players because irrespective of whether your team is in attacking or defensive mode there will inevitably be crucial one on one marking contests between individual players that will require a one player to properly execute a defensive spoil on the other.
But be careful! An incorrect method of spoiling will see the umpire award a free kick against you, thus gifting your opponent possession of the ball.
Check out the short video below for further tips on the art of defensive spoiling.