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®

wilful
     adj 1: done by design; "the insult was intentional"; "willful
            disobedience" [syn: {intentional}, {willful}]
     2: habitually disposed to disobedience and opposition [syn: {froward},
         {headstrong}, {self-willed}, {willful}]
     3: by conscious design or purpose; "intentional damage"; "a
        knowing attempt to defraud"; "a willful waste of time"
        [syn: {deliberate}, {intentional}, {knowing}, {willful}]