firefighter vs ranger

firefighter and ranger both are nouns.

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

As nouns, ranger is a hyponym of firefighter; that is, ranger is a word with a more specific, narrower meaning than firefighter:

firefighter: a member of a fire department who tries to extinguish fires
ranger: an official who is responsible for managing and protecting an area of forest

Other hyponyms of firefighter include fire chief, fire marshal, fire warden, forest fire fighter.

firefighter (noun)	ranger (noun)
a member of a fire department who tries to extinguish fires	an official who is responsible for managing and protecting an area of forest
	a member of a military unit trained as shock troops for hit-and-run raids