trackless trolley vs trolleybus

trackless trolley and trolleybus both are nouns.

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

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

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

Other synonyms of trackless trolley include trolley coach.

trackless trolley (noun)	trolleybus (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