trolleybus vs passenger vehicle

trolleybus and passenger vehicle both are nouns.

Word	Noun	Adjective	Verb	Adverb
trolleybus	Yes	No	No	No
passenger vehicle	Yes	No	No	No

As nouns, passenger vehicle is a hypernym of trolleybus; that is, passenger vehicle is a word with a broader meaning than trolleybus:

trolleybus: a passenger bus with an electric motor that draws power from overhead wires
passenger vehicle: a vehicle carrying many passengers; used for public transport

Other hypernyms of trolleybus include autobus, bus, charabanc, coach, double-decker, jitney, motorbus, motorcoach, omnibus.

trolleybus (noun)	passenger vehicle (noun)
a passenger bus with an electric motor that draws power from overhead wires	a vehicle carrying many passengers; used for public transport