1. a machine for driving piles, usually composed of a tall framework in which either a weight is raised and dropped on a pile head or in which a steam hammer drives the pile.
2. a person who operates such a machine.
3. a person who hits or attacks forcefully or powerfully.
4. Wrestling.a move whereby an opponent is turned upside down and slammed headfirst to the mat.
5. Brit. Sports.a powerful stroke, hit, kick, etc.