religious cult vs religion

religious cult and religion both are nouns.

Word	Noun	Adjective	Verb	Adverb
religious cult	Yes	No	No	No
religion	Yes	No	No	No

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

religious cult: a system of religious beliefs and rituals
religion: a strong belief in a supernatural power or powers that control human destiny

Other hypernyms of religious cult include faith, religious belief.

religious cult (noun)	religion (noun)
a system of religious beliefs and rituals	a strong belief in a supernatural power or powers that control human destiny
	an institution to express belief in a divine power