pagan religion vs religion

pagan religion and religion both are nouns.

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

As nouns, religion is a hypernym of pagan religion; that is, religion is a word with a broader meaning than pagan religion:

pagan religion: any of various religions other than Christianity or Judaism or Islamism
religion: a strong belief in a supernatural power or powers that control human destiny

Other hypernyms of pagan religion include faith, religious belief.

pagan religion (noun)	religion (noun)
any of various religions other than Christianity or Judaism or Islamism	a strong belief in a supernatural power or powers that control human destiny
	an institution to express belief in a divine power