used-car vs automobile

used-car and automobile both are nouns.

Word	Noun	Adjective	Verb	Adverb
used-car	Yes	No	No	No
automobile	Yes	No	Yes	No

As nouns, automobile is a hypernym of used-car; that is, automobile is a word with a broader meaning than used-car:

used-car: a car that has been previously owned; not a new car
automobile: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other hypernyms of used-car include auto, car, machine, motorcar.

used-car (noun)	automobile (noun)
a car that has been previously owned; not a new car	a motor vehicle with four wheels; usually propelled by an internal combustion engine

used-car (verb)	automobile (verb)
	travel in an automobile