noun

1. the projecting part of the head of a dog, horse, etc., including the mouth, nose, and jaws; snout
2. a device, as of straps, fastened over the mouth of an animal to prevent its biting or eating
3. anything that prevents free speech or discussion
4. the front end of the barrel of a firearm

Etymology: ME mosel < OFr musel, snout, muzzle, dim. of mus < ML musum < ?

transitive verb muzzled -·zled, muzzling -·zling

1. to put a muzzle on (an animal)
2. to prevent from talking or expressing an opinion; gag