cottonmouth moccasin vs water moccasin

cottonmouth moccasin and water moccasin both are nouns.

Word	Noun	Adjective	Verb	Adverb
cottonmouth moccasin	Yes	No	No	No
water moccasin	Yes	No	No	No

As nouns, cottonmouth moccasin and water moccasin are synonyms defined as:

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

Other synonyms of cottonmouth moccasin include Agkistrodon piscivorus, cottonmouth.

cottonmouth moccasin (noun)	water moccasin (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