soberness vs graveness

soberness and graveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
soberness	Yes	No	No	No
graveness	Yes	No	No	No

As nouns, soberness and graveness are synonyms defined as:

Other synonyms of soberness include gravity, sobriety, somberness, sombreness.

soberness (noun)	graveness (noun)
a manner that is serious and solemn	a manner that is serious and solemn
the state of being sober and not intoxicated by alcohol