Source : Webster's Revised Unabridged Dictionary (1913)

Bandit \Ban"dit\, n.; pl. {Bandits}, or {Banditti}. [It. bandito
   outlaw, p. p. of bandire to proclaim, to banish, to
   proscribe, LL. bandire, bannire. See {Ban} an edict, and cf.
   {Banish}.]
   An outlaw; a brigand.

         No savage fierce, bandit, or mountaineer. --Milton.

   Note: The plural banditti was formerly used as a collective
         noun.

               Deerstealers are ever a desperate banditti. --Sir
                                                  W. Scott.