Source : Webster's Revised Unabridged Dictionary (1913)

Rapacious \Rapa"cious\, a. [L. rapax, -acis, from rapere to
   seize and carry off, to snatch away. See {Rapid}.]
   1. Given to plunder; disposed or accustomed to seize by
      violence; seizing by force. `` The downfall of the
      rapacious and licentious Knights Templar.'' --Motley.

   2. Accustomed to seize food; subsisting on prey, or animals
      seized by violence; as, a tiger is a rapacious animal; a
      rapacious bird.

   3. Avaricious; grasping; extortionate; also, greedy;
      ravenous; voracious; as, rapacious usurers; a rapacious
      appetite.

            [Thy Lord] redeem thee from Death's rapacious claim
                                                  --Milton.

   Syn: Greedy; grasping; ravenous; voracious. --
        {Ra*pa"cious*ly}, adv. -- {Ra*pa"cious*ness}, n.

Source : WordNet®

rapaciously
     adv : in a rapacious manner