WordWeb Online

1. Done by design
   "willful disobedience";
   - wilful [Brit, Cdn]
    
2. Habitually disposed to disobedience and opposition
   "The relationship between the intellect and the emotions is like the relationship between parents and their willful five-year-old";
   - froward [archaic], headstrong, self-willed, wilful [Brit, Cdn]

See also: disobedient, voluntary

Encyclopedia: Willful