Possibly derived from the given name Ezzo (see Azzo), from an Italianized form of Germanic Hitz or Hilz (from hildiz "battle, fight"), or from a short form of any of several names ending with -izzo, such as Bonizzo, Obizzo, or Abizzo.
Could be a nickname for someone of Arabic or Saracen heritage, or who had dark hair and skin, derived from archaic Italian izzo, ultimately from Ancient Greek Αἰγύπτιος (Aigyptios) "Egyptian". The same word was also used for several kinds of birds of prey.