Source : Webster's Revised Unabridged Dictionary (1913)

Wilful \Wil"ful\, a., Wilfully \Wil"ful*ly\, adv., Wilfulness
\Wil"ful*ness\, n.
   See {Willful}, {Willfully}, and {Willfulness}.

Source : WordNet®

wilfulness
     n : the trait of being prone to disobedience and lack of
         discipline [syn: {unruliness}, {fractiousness}, {willfulness}]