trancejeremy
Adventurer
I have in mind enchantments, summoning and polymorph spells, which are all wizard's spells. But maybe that's just one type of witch... which other spells do you have in mind?
Just to but in, personally I've always seen the Witch as being somewhere between a Cleric and a Wizard, sharing some of the spells of both (AD&D actually does this by having the "Witch Doctor" for humanoid monsters), but also having some of their own.
But I think there are a lot of possibilities. It's a very evocative word - you can either stick an adjective in front of it, like say the Wicked Witch or Fire Witch or Moonlight Witch (to use examples from other media) or you can use it as an adjective - Witch Queen, Witch Blade, etc. It taps into the psyche in a way that more generic words don't.