cultus vs religious belief

cultus and religious belief both are nouns.

Word	Noun	Adjective	Verb	Adverb
cultus	Yes	No	No	No
religious belief	Yes	No	No	No

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

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

Other hypernyms of cultus include faith, religion.

cultus (noun)	religious belief (noun)
a system of religious beliefs and rituals	a strong belief in a supernatural power or powers that control human destiny