passenger vs rider

passenger and rider both are nouns.

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

As nouns, passenger and rider are synonyms defined as:

passenger and rider: a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it

passenger (noun)	rider (noun)
a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it	a clause that is appended to a legislative bill
	a traveler who actively rides an animal (as a horse or camel)
	a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it
	a traveler who actively rides a vehicle (as a bicycle or motorcycle)