witch's brew vs variety

witch's brew and variety both are nouns.

Word	Noun	Adjective	Verb	Adverb
witch's brew	Yes	No	No	No
variety	Yes	No	No	No

As nouns, variety is a hypernym of witch's brew; that is, variety is a word with a broader meaning than witch's brew:

Other hypernyms of witch's brew include assortment, miscellanea, miscellany, mixed bag, mixture, motley, potpourri, salmagundi, smorgasbord.

witch's brew (noun)	variety (noun)
a fearsome mixture	noticeable heterogeneity
	a difference that is usually pleasant
	a category of things distinguished by some common characteristic or quality
	a show consisting of a series of short unrelated performances
	(biology) a taxonomic category consisting of members of a species that differ from others of the same species in minor but heritable characteristics
	a collection containing a variety of sorts of things