black magic vs black art

black magic and black art both are nouns.

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

As nouns, black magic and black art are synonyms defined as:

black magic and black art: the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world

Other synonyms of black magic include necromancy, sorcery.

black magic (noun)	black art (noun)
the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world	the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world