The Collaborative International Dictionary of English v.0.48:

Laborsome \La"bor*some\, a.
   1. Made with, or requiring, great labor, pains, or diligence.
      [Obs.] --Shak.
      [1913 Webster]

   2. (Naut.) Likely or inclined to roll or pitch, as a ship in
      a heavy sea; having a tendency to labor.
      [1913 Webster]