What is Willful?

Legal Definition
Proceeding from a conscious motion of the will; intending the result which actually comes to pass; designed; intentional ; malicious. A willful differs essentially from a negligent act. The one is positive and the other negative. Intention is always separated from negligence by a precise line" of demarkation. Sturm v. Atlantic Mut. Ins. Co., 38 N. Y. Super. Ct. 317. In common parlance, "willful" is used in the Sense of "intentional," as distinguished from "accidental" or "involuntary." But language of a statute affixing a punishment to acts done willfully may be restricted to such acts done with an unlawful intent. U. S. v. Boyd (C. O.) 45 Fed. 855; State v. Clark, 29 N. J. Law, 96.
-- Black's Law Dictionary
Legal Definition
Ordinarily means intentional as distinguished from accidental or involuntary, but in penal statutes it means with evil intent or legal malice, or without reasonable ground to believe the act lawful. See 55 Tex. Cr. 164, 131 Am. St. Rep. 809, 115 S. W. 597.
-- Ballentine's Law Dictionary