racing car vs automobile

racing car and automobile both are nouns.

Word	Noun	Adjective	Verb	Adverb
racing car	Yes	No	No	No
automobile	Yes	No	Yes	No

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

racing car: a fast car that competes in races
automobile: a motor vehicle with four wheels; usually propelled by an internal combustion engine

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

racing car (noun)	automobile (noun)
a fast car that competes in races	a motor vehicle with four wheels; usually propelled by an internal combustion engine

racing car (verb)	automobile (verb)
	travel in an automobile