vermillion vs cinnabar

vermillion is not a noun while cinnabar is a noun.

Word	Noun	Adjective	Verb	Adverb
vermillion	No	Yes	No	No
cinnabar	Yes	Yes	No	No

As adjectives, vermillion and cinnabar are synonyms defined as:

Other synonyms of vermillion include Chinese-red, vermilion.

vermillion (noun)	cinnabar (noun)
	large red-and-black European moth; larvae feed on leaves of ragwort; introduced into United States to control ragwort
	a heavy reddish mineral consisting of mercuric sulfide; the chief source of mercury

vermillion (adjective)	cinnabar (adjective)
of a vivid red to reddish-orange color	of a vivid red to reddish-orange color