demonism vs black art

demonism and black art both are nouns.

Word	Noun	Adjective	Verb	Adverb
demonism	Yes	No	No	No
black art	Yes	No	No	No

As nouns, black art is a hypernym of demonism; that is, black art is a word with a broader meaning than demonism:

demonism: a belief in and reverence for devils (especially Satan)
black art: the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world

Other hypernyms of demonism include black magic, necromancy, sorcery.

demonism (noun)	black art (noun)
a belief in and reverence for devils (especially Satan)	the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world