passenger vs commuter

passenger and commuter both are nouns.

Word	Noun	Adjective	Verb	Adverb
passenger	Yes	No	No	No
commuter	Yes	No	No	No

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

passenger: a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it
commuter: someone who travels regularly from home in a suburb to work in a city

Other hyponyms of passenger include fare, hitchhiker, stowaway, straphanger.

passenger (noun)	commuter (noun)
a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it	a passenger train that is ridden primarily by passengers who travel regularly from one place to another
	someone who travels regularly from home in a suburb to work in a city