Source : Webster's Revised Unabridged Dictionary (1913)

--E. Everett.

   3. Full of promise; abounding in ability, resources, etc.;
      as, a pregnant youth. [Obs.] --Evelyn.

            Wherein the pregnant enemy does much. --Shak.

   {Pregnant construction} (Rhet.), one in which more is implied
      than is said; as, the beasts trembled forth from their
      dens, that is, came forth trembling with fright.