rental vs hire car

rental and hire car both are nouns.

Word	Noun	Adjective	Verb	Adverb
rental	Yes	Yes	No	No
hire car	Yes	No	No	No

As nouns, hire car is a hyponym of rental; that is, hire car is a word with a more specific, narrower meaning than rental:

Other hyponyms of rental include car rental, rent-a-car, self-drive, u-drive, you-drive, sublease, sublet.

rental (noun)	hire car (noun)
the act of paying for the use of something (as an apartment or house or car)	a rented car
property that is leased or rented out or let

rental (adjective)	hire car (adjective)
of or relating to rent
available to rent or lease