firefighter vs fireman

firefighter and fireman both are nouns.

Word	Noun	Adjective	Verb	Adverb
firefighter	Yes	No	No	No
fireman	Yes	No	No	No

As nouns, firefighter and fireman are synonyms defined as:

firefighter and fireman: a member of a fire department who tries to extinguish fires

Other synonyms of firefighter include fire-eater, fire fighter.

firefighter (noun)	fireman (noun)
a member of a fire department who tries to extinguish fires	play in which children pretend to put out a fire
	a member of a fire department who tries to extinguish fires
	a laborer who tends fires (as on a coal-fired train or steamship)
	a pitcher who does not start the game