trolleybus vs trackless trolley

trolleybus and trackless trolley both are nouns.

Word	Noun	Adjective	Verb	Adverb
trolleybus	Yes	No	No	No
trackless trolley	Yes	No	No	No

As nouns, trolleybus and trackless trolley are synonyms defined as:

trolleybus and trackless trolley: a passenger bus with an electric motor that draws power from overhead wires

Other synonyms of trolleybus include trolley coach.

trolleybus (noun)	trackless trolley (noun)
a passenger bus with an electric motor that draws power from overhead wires	a passenger bus with an electric motor that draws power from overhead wires