The Collaborative International Dictionary of English v.0.48:

Pickpocket \Pick"pock`et\, n.
   One who steals purses or other articles from pockets.
   --Bentley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pickpocket
    n 1: a thief who steals from the pockets or purses of others in
         public places [syn: pickpocket, cutpurse, dip]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

PICKPOCKET. A thief; one who in a crowd or. in other places, steals from the
pockets or person of another without putting him in fear. This is generally
punished as simple larceny.