water moccasin vs Agkistrodon piscivorus

water moccasin and Agkistrodon piscivorus both are nouns.

Word	Noun	Adjective	Verb	Adverb
water moccasin	Yes	No	No	No
Agkistrodon piscivorus	Yes	No	No	No

As nouns, water moccasin and Agkistrodon piscivorus are synonyms defined as:

water moccasin and Agkistrodon piscivorus: venomous semiaquatic snake of swamps in southern United States

Other synonyms of water moccasin include cottonmouth, cottonmouth moccasin.

water moccasin (noun)	Agkistrodon piscivorus (noun)
venomous semiaquatic snake of swamps in southern United States	venomous semiaquatic snake of swamps in southern United States
any of numerous North American water snakes inhabiting fresh waters