The Collaborative International Dictionary of English v.0.48:

Laboring \La"bor*ing\, a.
   1. That labors; performing labor; esp., performing coarse,
      heavy work, not requiring skill also, set apart for labor;
      as, laboring days.
      [1913 Webster]

            The sleep of a laboring man is sweet. --Eccl. v. 12.
      [1913 Webster]

   2. Suffering pain or grief. --Pope.
      [1913 Webster]

   Laboring oar, the oar which requires most strength and
      exertion; often used figuratively; as, to have, or pull,
      the laboring oar in some difficult undertaking.
      [1913 Webster]