The Collaborative International Dictionary of English v.0.48:

Revengeful \Re*venge"ful\, a.
   Full of, or prone to, revenge; vindictive; malicious;
   revenging; wreaking revenge.
   [1913 Webster]

         If thy revengeful heart can not forgive. --Shak.
   [1913 Webster]

         May my hands . . .
         Never brandish more revengeful steel.    --Shak.
   [1913 Webster]

   Syn: Vindictive; vengeful; resentful; malicious.
        [1913 Webster] -- Re*venge"ful*ly, adv. --
        Re*venge"ful*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

revengeful
    adj 1: disposed to seek revenge or intended for revenge; "more
           vindictive than jealous love"- Shakespeare;
           "punishments...essentially vindictive in their nature"-
           M.R.Cohen [syn: revengeful, vindictive, vengeful]