Source : Webster's Revised Unabridged Dictionary (1913)

Ply \Ply\, v. t. [imp. & p. p. {Plied}; p. pr. & vb. n.
   {Plying}.] [OE. plien, F. plier to fold, to bend, fr. L.
   plicare; akin to Gr. ?, G. flechten. Cf. {Apply}, {Complex},
   {Display}, {Duplicity}, {Employ}, {Exploit}, {Implicate},
   {Plait}, {Pliant}, {Flax}.]
   1. To bend. [Obs.]

            As men may warm wax with handes plie. --Chaucer.

   2. To lay on closely, or in folds; to work upon steadily, or
      with repeated acts; to press upon; to urge importunately;
      as, to ply one with questions, with solicitations, or with
      drink.

            And plies him with redoubled strokes  --Dryden.

            He plies the duke at morning and at night. --Shak.

   3. To employ diligently; to use steadily.

            Go ply thy needle; meddle not.        --Shak.

   4. To practice or perform with diligence; to work at.

            Their bloody task, unwearied, still they ply.
                                                  --Waller.