Muzzle

the open circular discharging end of a gun

forward projecting part of the head of certain animals

a leather or wire restraint that fits over an animal's snout (especially a dog's nose and jaws) and prevents it from eating or biting

restraint put into a person's mouth to prevent speaking or shouting

fit with a muzzle

prevent from speaking out

tie a gag around someone's mouth in order to silence them