misbeliever vs castaway

misbeliever and castaway both are nouns.

Word	Noun	Adjective	Verb	Adverb
misbeliever	Yes	No	No	No
castaway	Yes	No	No	No

As nouns, castaway is a hypernym of misbeliever; that is, castaway is a word with a broader meaning than misbeliever:

misbeliever: a person who holds religious beliefs in conflict with the dogma of the Roman Catholic Church
castaway: a person who is rejected (from society or home)

Other hypernyms of misbeliever include Ishmael, outcast, pariah.

misbeliever (noun)	castaway (noun)
a person who holds religious beliefs in conflict with the dogma of the Roman Catholic Church	a shipwrecked person
	a person who is rejected (from society or home)