Shintoism vs religious belief

Shintoism and religious belief both are nouns.

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

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

Shintoism: the ancient indigenous religion of Japan lacking formal dogma; characterized by a veneration of nature spirits and of ancestors
religious belief: a strong belief in a supernatural power or powers that control human destiny

Other hypernyms of Shintoism include faith, religion.

Shintoism (noun)	religious belief (noun)
the ancient indigenous religion of Japan lacking formal dogma; characterized by a veneration of nature spirits and of ancestors	a strong belief in a supernatural power or powers that control human destiny