Witch is not a technical term in DnD. You could have a "witch" who is a Wizard, a Sorcerer, a Warlock or even a Cleric.
But remember that even though wizard and sorcerer and what not are technical terms in the context of mechanics, in in-world terms they're just synonyms and different words for people who do magic.
Witch is also gender neutral, even if it's mostly used as feminine in our modern world. If anything is a male-gendered version of witch it is witcher (even though that is just a version of the same).
