Boothaler: marauder, plunderer
Burglar: one who breaks into, and steals things from, other people's houses. (If you break into and steal stuff from your own house, you're just a nut.)
Diver: fig. a pickpocket
Fence: one who trades in stolen goods
Footpad: one who robs pedestrians
Outlaw: a man wanted by the law
Pickpocket: one who picks pockets
Poacher: one who illegally kills animals, usually on somebody else's land
Silk-snatcher: one who steals bonnets
Stewsman: probably a brothel keeper - "since the words stew and stewholder both mean a bawd, I'm guessing that a stewsman would be a brothel-keeper as well. Whether bawdry counts as a criminal activity varies at different times and places."
Thimblerigger: a professional sharper who runs a thimblerig (a game in which a pea is ostensibly hidden under a thimble and players guess which thimble it is under)
(Found on http://www.svincent.com/MagicJar/Economics/MedievalOccupations.html)