Source : Webster's Revised Unabridged Dictionary (1913)

Vanquish \Van"quish\, v. t. [imp. & p. p. {Vanquished}; p. pr. &
   vb. n. {Vanquishing}.] [OE. venquishen, venquissen,
   venkisen,F. vaincre, pret. vainquis, OF. veintre, pret.
   venqui, venquis (cf. an OF. infin. vainquir), fr. L. vincere;
   akin to AS. w[=i]g war, battle, w[=i]gant a warrior, w[=i]gan
   to fight, Icel. v[=i]g battle, Goth. weihan to fight,
   contend. Cf. {Convince}, {Evict}, {Invincible}, {Victor}.]
   1. To conquer, overcome, or subdue in battle, as an enemy.
      --Hakluyt.

            They . . . Vanquished the rebels in all encounters.
                                                  --Clarendon.

   2. Hence, to defeat in any contest; to get the better of; to
      put down; to refute.

            This bold assertion has been fully vanquished in a
            late reply to the Bishop of Meaux's treatise.
                                                  --Atterbury.

            For e'en though vanquished, he could argue still.
                                                  --Goldsmith.

   Syn: To conquer; surmount; overcome; confute; silence. See
        {Conquer}.