banditry (n.)

"lawless robber, brigand" (especially as part of an organized band), 1590s, from Italian bandito (plural banditi) "outlaw," past participle of bandire "proscribe, banish," from Vulgar Latin *bannire "to proclaim, proscribe," from Proto-Germanic *bannan "to speak publicly" (used in reference to various sorts of proclamations), "command; summon; outlaw, forbid" (see ban (v.)).

Vulgar Latin *bannire (or its Frankish cognate *bannjan) in Old French became banir, which, with lengthened stem, became English banish.

reduced form of -ery.