When the gods of magic created the Orders of High Sorcery, they did so to preserve the balance of magic in the world. Those who did not or would not follow the laws of magic were to be considered renegades.
A renegade wizard is any wizard who exists outside the Orders of High Sorcery, and whose usage of magic is considered a thread to the balance as well as a threat to the fragile image of the Mages of High Sorcery. A renegade wizard whose magic is terrorizing a small village is still a wizard to the villagers, no matter what kind of robes he wears.