classic vs Graeco-Roman

classic is a noun but Graeco-Roman is not a noun.

Word	Noun	Adjective	Verb	Adverb
classic	Yes	Yes	No	No
Graeco-Roman	No	Yes	No	No

classic (noun)	Graeco-Roman (noun)
a creation of the highest excellence
an artist who has created classic works

classic (adjective)	Graeco-Roman (adjective)
of or relating to the first significant period of a civilization, culture, area of study, etc.	of or pertaining to or characteristic of the ancient Greeks and Romans, especially their art, literature, or culture
considered of the highest quality and lasting significance or worth
well-known and long-established in form or style
of a well-known type; remarkably typical