The Collaborative International Dictionary of English v.0.48:

Sutler \Sut"ler\, n. [D. zoetelaar, OD. soetelaar, a small
   trader, especially in camps, fr. soetelen to undertake low
   offices; cf. G. sudeln to do dirty work, to sully, soil, E.
   suds.]
   A person who follows an army, and sells to the troops
   provisions, liquors, and the like.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sutler
    n 1: a supplier of victuals or supplies to an army [syn:
         sutler, victualer, victualler, provisioner]