ring-necked snake vs ringneck snake

ring-necked snake and ringneck snake both are nouns.

Word	Noun	Adjective	Verb	Adverb
ring-necked snake	Yes	No	No	No
ringneck snake	Yes	No	No	No

As nouns, ring-necked snake and ringneck snake are synonyms defined as:

ring-necked snake and ringneck snake: any of numerous small nonvenomous North American snakes with a yellow or orange ring around the neck

Other synonyms of ring-necked snake include ring snake.

ring-necked snake (noun)	ringneck snake (noun)
any of numerous small nonvenomous North American snakes with a yellow or orange ring around the neck	any of numerous small nonvenomous North American snakes with a yellow or orange ring around the neck