Willfully Definition: Acting voluntarily, deliberately and intentionally. Related Terms: Knowingly "Willfully means that a defendant acted knowingly, deliberately, and intentionally as contrasted with accidentally, carelessly or unintentionally."Willfully means a voluntary, intentional violation of a known legal duty. In other words, the defendant must have acted voluntarily and intentionally and with the specific intent to do something that the law forbids; that is to say, with a purpose either to disobey or disregard the law." Compare with Legal Definition of Knowingly. REFERENCES:US v De Castro-Font, 587 F. Supp. 2d 372 (2008; Footnote #1) Categories & Topics: Criminal Law Dictionary Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!