fire fighter vs firefighter

fire fighter and firefighter both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire fighter	Yes	No	No	No
firefighter	Yes	No	No	No

As nouns, fire fighter and firefighter are synonyms defined as:

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

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

fire fighter (noun)	firefighter (noun)
a member of a fire department who tries to extinguish fires	a member of a fire department who tries to extinguish fires