amphibian vs pontoon

amphibian and pontoon both are nouns.

Word	Noun	Adjective	Verb	Adverb
amphibian	Yes	Yes	No	No
pontoon	Yes	No	No	No

amphibian (noun)	pontoon (noun)
cold-blooded vertebrate typically living on land but breeding in water; aquatic larvae undergo metamorphosis into adult form	a float supporting a seaplane
an airplane designed to take off and land on water	(nautical) a floating structure (as a flat-bottomed boat) that serves as a dock or to support a bridge
a flat-bottomed motor vehicle that can travel on land or water

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