hit man vs gunslinger

hit man and gunslinger both are nouns.

Word	Noun	Adjective	Verb	Adverb
hit man	Yes	No	No	No
gunslinger	Yes	No	No	No

As nouns, hit man and gunslinger are synonyms defined as:

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

hit man (noun)	gunslinger (noun)
a professional killer who uses a gun	a professional killer who uses a gun