The Collaborative International Dictionary of English v.0.48:

Chapman \Chap"man\, n.; pl. Chapmen. [AS. ce['a]pman; ce['a]p
   trade + man man; akin to D. koopman, Sw. k["o]pman, Dan.
   ki["o]pmand, G. kaufmann.f. Chap to cheapen, and see
   Cheap.]
   1. One who buys and sells; a merchant; a buyer or a seller.
      [Obs.]
      [1913 Webster]

            The word of life is a quick commodity, and ought
            not, as a drug to be obtruded on those chapmen who
            are unwilling to buy it.              --T. Fuller.
      [1913 Webster]

   2. A peddler; a hawker.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Chapman
    n 1: United States pioneer who planted apple trees as he
         traveled (1774-1845) [syn: Chapman, John Chapman,
         Johnny Appleseed]
    2: archaic term for an itinerant peddler