amphibian vs motor vehicle

amphibian and motor vehicle both are nouns.

Word	Noun	Adjective	Verb	Adverb
amphibian	Yes	Yes	No	No
motor vehicle	Yes	No	No	No

As nouns, motor vehicle is a hypernym of amphibian; that is, motor vehicle is a word with a broader meaning than amphibian:

Other hypernyms of amphibian include automotive vehicle.

amphibian (noun)	motor vehicle (noun)
cold-blooded vertebrate typically living on land but breeding in water; aquatic larvae undergo metamorphosis into adult form	a self-propelled wheeled vehicle that does not run on rails
an airplane designed to take off and land on water
a flat-bottomed motor vehicle that can travel on land or water

amphibian (adjective)	motor vehicle (adjective)
relating to or characteristic of animals of the class Amphibia