Source : Webster's Revised Unabridged Dictionary (1913)

Vindictive \Vin*dic"tive\, a. [For vindicative, confused with L.
   vindicta revenge, punishment, fr. vindicare to vindicate. Cf.
   {Vindicative}.]
   1. Disposed to revenge; prompted or characterized by revenge;
      revengeful.

            I am vindictive enough to repel force by force.
                                                  --Dryden.

   2. Punitive. [Obs.]

   {Vindictive damages}. (Law) See under {Damage}, n. --
      {Vin*dic"tive*ly}, adv. -- {Vin*dic"tive*ness}, n.

Source : WordNet®

vindictively
     adv : in a vindictive, revengeful manner; "he plotted vindictively
           against his former superiors" [syn: {revengefully}, {vengefully}]