The Collaborative International Dictionary of English v.0.48:

Landman \Land"man\, n.; pl. Landmen.
   1. A man who lives or serves on land; -- opposed to seaman.
      [1913 Webster]

   2. (Eng.) An occupier of land. --Cowell.
      [1913 Webster]

WordNet (r) 3.0 (2006):

landman
    n 1: a person who lives and works on land [syn: landlubber,
         landsman, landman]