Committing a Foul
Players use their hips and shoulders to hit other players if the player has the puck or has just passed it. This is called body-checking and is perfectely legal. The following are forbidden and incur penalties:
Boarding: Throwing an opponent violently into the boards.
Butt-Ending: Jabbing an opponent with the shaft of one's stick.
Charging: Taking more than two steps towards an opponent before body checking him.
Clipping: Throwing one's body below an opponents knees.
Cross-Checking: Hitting an opponent with the shaft of the stick while both hands are on the shaft.
Elbowing: Impeding or striking an opponent with one' elbow.
Delay of Game: Failing to keep the puck in motion.
High-Sticking: Hitting an opponent above the shoulders.
Holding: Impeding an opponent with hands or arms.
Hooking: Impeding an opponent with one's stick.
Interference: Body-checking an opponent who does not have the puck or who has just passed it.
Kneeing: Hitting an opponent with one's knee.
Slashing: Swinging one's stick at an opponent.
Spearing: Jabbing an opponent with the blade of one's stick.
Tripping: Impeding an opponent around his legs.
Officials Signals
There are two categories of officials: on ice officials are the referees and linesmen that enforce the rules during game play; off-ice officials have an administrative role rather than an enforecement role. The referee will halt the game using a whistle followed by a signal when he spots any of the offences outlined above. The signals used in ice hockey are unique to the game. There are more than a dozen signals used by referees, below are some of the most commonly seen during a game.