From WordNet (r) 3.0 (2006) [wn]:
wilfully
adv 1: in a willful manner; "she had willfully deceived me"
[syn: willfully, wilfully]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Wilful \Wil"ful\, a., Wilfully \Wil"ful*ly\, adv., Wilfulness
\Wil"ful*ness\, n.
See Willful, Willfully, and Willfulness.
[1913 Webster]