cinnabar vs vermillion

cinnabar is a noun but vermillion is not a noun.

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

As adjectives, cinnabar and vermillion are synonyms defined as:

Other synonyms of cinnabar include Chinese-red, vermilion.

cinnabar (noun)	vermillion (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

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