(Ice) hockey:
A hard, fast but sometimes inaccurate shot.
The shooter raises his stick high on the backswing, hands far apart on the hockey stick, and then leans hard into the stick on the forehand shot. Slapshots can travel at up to 120 miles per hour, but not even the shooter can tell exactly where they are going to go.
St. Louis Blues defenseman Al MacInnis had one of the hardest shots in the NHL. Goalies would cringe at the sight of Al winding up from the blue line.