laboring \la"boring\, 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
see also:
laboring oar