Source : Webster's Revised Unabridged Dictionary (1913)

Perversity \Per*ver"si*ty\, n. [L. perversitas: cf. F.
   perversit['e].]
   The quality or state of being perverse; perverseness.

Source : WordNet®

perversity
     n 1: deliberate unruliness [syn: {contrariness}, {perverseness}]
     2: deliberately deviating from what is good