hardtop vs automobile

hardtop and automobile both are nouns.

Word	Noun	Adjective	Verb	Adverb
hardtop	Yes	No	No	No
automobile	Yes	No	Yes	No

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

hardtop: a car that resembles a convertible but has a fixed rigid top
automobile: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other hypernyms of hardtop include auto, car, machine, motorcar.

hardtop (noun)	automobile (noun)
a car that resembles a convertible but has a fixed rigid top	a motor vehicle with four wheels; usually propelled by an internal combustion engine

hardtop (verb)	automobile (verb)
	travel in an automobile