motor vehicle vs truck

motor vehicle and truck both are nouns.

Word	Noun	Adjective	Verb	Adverb
motor vehicle	Yes	No	No	No
truck	Yes	No	Yes	No

As nouns, truck is a hyponym of motor vehicle; that is, truck is a word with a more specific, narrower meaning than motor vehicle:

motor vehicle (noun)	truck (noun)
a self-propelled wheeled vehicle that does not run on rails	an automotive vehicle suitable for hauling
	a handcart that has a frame with two low wheels and a ledge at the bottom and handles at the top; used to move crates or other heavy objects

motor vehicle (verb)	truck (verb)
	convey (goods etc.) by truck