mountain blacksnake vs pilot blacksnake

mountain blacksnake and pilot blacksnake both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain blacksnake	Yes	No	No	No
pilot blacksnake	Yes	No	No	No

As nouns, mountain blacksnake and pilot blacksnake are synonyms defined as:

mountain blacksnake and pilot blacksnake: large harmless shiny black North American snake

Other synonyms of mountain blacksnake include black rat snake, blacksnake, Elaphe obsoleta.

mountain blacksnake (noun)	pilot blacksnake (noun)
large harmless shiny black North American snake	large harmless shiny black North American snake