1. in a deliberate and intentional manner, especially when doing something wrong or harmful
Usage: British spelling; American spelling is ‘willfully’
2. in a stubborn or obstinate manner; refusing to change one’s mind or behavior
Usage: British spelling; American spelling is ‘willfully’

Examples

• He wilfully ignored the safety warnings and entered the restricted area.
• The defendant was charged with wilfully damaging public property.
• She wilfully refused to follow the new company policies.
• The child wilfully disobeyed his parents despite repeated warnings.
• The driver wilfully exceeded the speed limit in the school zone.
• He wilfully misunderstood her instructions to avoid doing the work.