sage-green vs sage

sage-green is not a noun while sage is a noun.

Word	Noun	Adjective	Verb	Adverb
sage-green	No	Yes	No	No
sage	Yes	Yes	No	No

As adjectives, sage-green and sage are synonyms defined as:

sage-green (noun)	sage (noun)
	aromatic fresh or dried grey-green leaves used widely as seasoning for meats and fowl and game etc
	a mentor in spiritual and philosophical topics who is renowned for profound wisdom
	any of various plants of the genus Salvia; a cosmopolitan herb

sage-green (adjective)	sage (adjective)
of the grey-green color of sage leaves	of the grey-green color of sage leaves
	having wisdom that comes with age and experience