muz·zle / ˈməzəl/ • n. 1. the projecting part of the face, including the nose and mouth, of an animal such as a dog or horse. ∎  a guard, typically made of straps or wire, fitted over this part of an animal's face to stop it from biting or feeding. ∎ inf. the part of a person's face including the nose, mouth, and chin. ∎ fig. any restraint on free speech: the muzzle the prime minister put on foreign journalists.2. the open end of the barrel of a firearm.• v. [tr.] put a muzzle on (an animal). ∎ fig. prevent (a person or an institution, esp. the press) from expressing their opinions freely: the politicians want to muzzle us and control what we write.

muzzle
A. beast's nose and mouth XV; open end of a gun XVI;

B. contrivance confining an animal's mouth XIV. ME. mosel — OF. musel (mod. museau):- Gallo-Rom. *mūsellum, dim. of medL. mūsum, of unkn. orig.
Hence vb. XV.