Webster's Revised Unabridged Dictionary · 1913

Bandit

Bandit (ban"dit) , noun

[Italian bandito outlaw, past participle of bandire to proclaim, to banish, to proscribe, Late Latin bandire, bannire. See Ban an edict, and compare Banish.]

An outlaw; a brigand.
No savage fierce, bandit, or mountaineer. — Milton
Deerstealers are ever a desperate banditti. — Sir W. Scott

The plural banditti was formerly used as a collective noun.