religion vs Christian

religion and Christian both are nouns.

Word	Noun	Adjective	Verb	Adverb
religion	Yes	No	No	No
Christian	Yes	Yes	No	No

religion (noun)	Christian (noun)
a strong belief in a supernatural power or powers that control human destiny	a religious person who believes Jesus is the Christ and who is a member of a Christian denomination
an institution to express belief in a divine power

religion (adjective)	Christian (adjective)
	relating to or characteristic of Christianity