hellbender vs mud puppy

hellbender and mud puppy both are nouns.

Word	Noun	Adjective	Verb	Adverb
hellbender	Yes	No	No	No
mud puppy	Yes	No	No	No

As nouns, hellbender and mud puppy are synonyms defined as:

hellbender and mud puppy: large salamander of North American rivers and streams

Other synonyms of hellbender include Cryptobranchus alleganiensis.

hellbender (noun)	mud puppy (noun)
large salamander of North American rivers and streams	aquatic North American salamander with red feathery external gills
	larval salamander of mountain lakes of Mexico that usually lives without metamorphosing
	large salamander of North American rivers and streams