witchcraft vs black magic

witchcraft and black magic both are nouns.

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

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

witchcraft: the art of sorcery
black magic: 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 art, necromancy, sorcery.

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