witchcraft vs black art

witchcraft and black art both are nouns.

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

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

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

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

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