The Collaborative International Dictionary of English v.0.48:

Landsman \Lands"man\, n.; pl. Landsmen.
   1. One who lives on the land; -- opposed to seaman.
      [1913 Webster]

   2. (Naut.) A sailor on his first voyage.
      [1913 Webster]

WordNet (r) 3.0 (2006):

landsman
    n 1: a person who lives and works on land [syn: landlubber,
         landsman, landman]
    2: an inexperienced sailor; a sailor on the first voyage [syn:
       landlubber, lubber, landsman]