The Collaborative International Dictionary of English v.0.48:

Dispiteous \Dis*pit"e*ous\, a. [Pref. dis- + piteous. Cf.
   Despiteous.]
   Full of despite; cruel; spiteful; pitiless. --Spenser. --
   Dis*pit"e*ous*ly, adv. [Obs.]
   [1913 Webster]