Akademik

wilful

adj. (US willful)
1 (of an action or state) intentional, deliberate (wilful murder; wilful neglect; wilful disobedience).
2 (of a person) obstinate, headstrong.
Derivatives:
wilfully adv. wilfulness n.
Etymology: ME f. WILL(2) + -FUL

Useful english dictionary. 2012.