gas guzzler vs auto

gas guzzler and auto both are nouns.

Word	Noun	Adjective	Verb	Adverb
gas guzzler	Yes	No	No	No
auto	Yes	No	No	No

As nouns, auto is a hypernym of gas guzzler; that is, auto is a word with a broader meaning than gas guzzler:

gas guzzler: a car with relatively low fuel efficiency
auto: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other hypernyms of gas guzzler include automobile, car, machine, motorcar.

gas guzzler (noun)	auto (noun)
a car with relatively low fuel efficiency	a motor vehicle with four wheels; usually propelled by an internal combustion engine