church member vs churchgoer

church member and churchgoer both are nouns.

Word	Noun	Adjective	Verb	Adverb
church member	Yes	No	No	No
churchgoer	Yes	No	No	No

As nouns, church member and churchgoer are synonyms defined as:

church member and churchgoer: a religious person who goes to church regularly

church member (noun)	churchgoer (noun)
a religious person who goes to church regularly	a religious person who goes to church regularly