sanguine vs rubicund

sanguine is a noun but rubicund is not a noun.

Word	Noun	Adjective	Verb	Adverb
sanguine	Yes	Yes	No	No
rubicund	No	Yes	No	No

As adjectives, sanguine and rubicund are synonyms defined as:

sanguine and rubicund: inclined to a healthy reddish color often associated with outdoor life

Other synonyms of sanguine include florid, ruddy.

sanguine (noun)	rubicund (noun)
chalk of a reddish-brown colour that resembles dried blood
a blood-red color

sanguine (adjective)	rubicund (adjective)
inclined to a healthy reddish color often associated with outdoor life	inclined to a healthy reddish color often associated with outdoor life
confidently optimistic and cheerful