As a Noun:
1. The determination to get what you want and to do things in your own way, often knowing you may hurt someone else. English = wilfulness.
2. The strong determination that someone has to do exactly what they want and not to change their mind or be persuaded to do anything else. English = obstinacy.
As a Verb or Adjective:
1. Of actions, to be done with intention or with a plan, that is after having thought about it first. English = (be) deliberate, (be) intentional, (be) done on purpose.
2. Of actions and attitudes, to be done or expressed deliberately, especially with the intention of hurting someone. English = (be) wilful.
3. Of someone's character, to be determined to get what you want and to do things in your own way. English = (be) wilful, (be) headstrong, (be) obstinate.
As Modifier:
1. Used immediately next to a verb to mean that the action was done with full knowledge or with a plan and not by accident, even though it may have a hurtful result for someone else. The person wanted to do the action.
2. English = deliberately, intentionally, on purpose, wilfully.