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n. A sharp blow delivered by driving the head into the opponent, generally by lowering the head and charging forward or by rapidly tilting the head backward and then forward.

v. To deliver a sharp blow by driving the head into an opponent.

v. butt with the head

"Wilkes lawyer Abigail Rogers argued that the headbutt was the only way her client could defend himself after being restrained by other parents."

bunt    butt   

Glasgow kiss    butt    butt heads with    butthead