The Collaborative International Dictionary of English v.0.48:

Despitous \De*spit"ous\, a.
   Despiteous; very angry; cruel. [Obs.]
   [1913 Webster]

         He was to sinful man not despitous.      --Chaucer.
   - De*spit"ous*ly, adv. [Obs.]
   [1913 Webster]