Doctor of the Church vs Roman Catholic

Doctor of the Church and Roman Catholic both are nouns.

Word	Noun	Adjective	Verb	Adverb
Doctor of the Church	Yes	No	No	No
Roman Catholic	Yes	Yes	No	No

Doctor of the Church (noun)	Roman Catholic (noun)
(Roman Catholic Church) a title conferred on 33 saints who distinguished themselves through the orthodoxy of their theological teaching	the Christian Church based in the Vatican and presided over by a pope and an episcopal hierarchy
	a member of the Roman Catholic Church

Doctor of the Church (adjective)	Roman Catholic (adjective)
	of or relating to or supporting Romanism