The Collaborative International Dictionary of English v.0.48:

Spiteful \Spite"ful\, a.
   Filled with, or showing, spite; having a desire to vex,
   annoy, or injure; malignant; malicious; as, a spiteful person
   or act. --Shak. -- Spite"ful*ly, adv. Spite"ful*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

spitefulness
    n 1: feeling a need to see others suffer [syn: malice,
         maliciousness, spite, spitefulness, venom]
    2: malevolence by virtue of being malicious or spiteful or nasty
       [syn: cattiness, bitchiness, spite, spitefulness,
       nastiness]