gun vs gunman

gun and gunman both are nouns.

Word	Noun	Adjective	Verb	Adverb
gun	Yes	No	Yes	No
gunman	Yes	No	No	No

As nouns, gun and gunman are synonyms defined as:

Other synonyms of gun include gun for hire, gunslinger, hired gun, hit man, hitman, shooter, torpedo, triggerman.

As nouns, gun and gunman are synonyms defined as:

gun (noun)	gunman (noun)
the discharge of a firearm as signal or as a salute in military ceremonies	a professional killer who uses a gun
a weapon that discharges a missile at high velocity (especially from a metal tube or barrel)	a person who shoots a gun (as regards their ability)
large but transportable armament
a hand-operated pump that resembles a pistol; forces grease into parts of a machine
a pedal that controls the throttle valve
a professional killer who uses a gun
a person who shoots a gun (as regards their ability)

gun (verb)	gunman (verb)
shoot with a gun