villain vs persona non grata

villain and persona non grata both are nouns.

Word	Noun	Adjective	Verb	Adverb
villain	Yes	No	No	No
persona non grata	Yes	No	No	No

As nouns, persona non grata is a hypernym of villain; that is, persona non grata is a word with a broader meaning than villain:

Other hypernyms of villain include unwelcome person.

villain (noun)	persona non grata (noun)
a wicked or evil person; someone who does evil deliberately	a person who for some reason is not wanted or welcome
the principal bad character in a film or work of fiction	a diplomat who is unacceptable to the government to which he is sent