Buddhist vs religious person

Buddhist and religious person both are nouns.

Word	Noun	Adjective	Verb	Adverb
Buddhist	Yes	Yes	No	No
religious person	Yes	No	No	No

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

Buddhist (noun)	religious person (noun)
one who follows the teachings of Buddha	a person who manifests devotion to a deity

Buddhist (adjective)	religious person (adjective)
of or relating to or supporting Buddhism