homeliness vs plainness

homeliness and plainness both are nouns.

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

As nouns, homeliness and plainness are synonyms defined as:

homeliness and plainness: an appearance that is not attractive or beautiful

homeliness (noun)	plainness (noun)
an appearance that is not attractive or beautiful	the appearance of being plain and unpretentious
having a drab or dowdy quality; lacking stylishness or elegance	an appearance that is not attractive or beautiful
	clarity as a consequence of being perspicuous
	the state of being unmixed with other material