plainness vs bareness

plainness and bareness both are nouns.

Word	Noun	Adjective	Verb	Adverb
plainness	Yes	No	No	No
bareness	Yes	No	No	No

As nouns, bareness is a hyponym of plainness; that is, bareness is a word with a more specific, narrower meaning than plainness:

Other hyponyms of plainness include chasteness, restraint, simpleness, simplicity, austereness, severeness, severity, starkness.

plainness (noun)	bareness (noun)
the appearance of being plain and unpretentious	an extreme lack of furnishings or ornamentation
an appearance that is not attractive or beautiful	the state of being unclothed and exposed (especially of a part of the body)
clarity as a consequence of being perspicuous	a bleak and desolate atmosphere
the state of being unmixed with other material