A deadly weapon is an object, instrument, substance, or device which is intended to be used in a way that is likely to cause death, or with which death can be easily and readily produced.
A deadly weapon need not be a weapon in the traditional sense. For example, in Acers v. United States the Supreme Court acknowledged that a large rock could be considered a deadly weapon when used by a defendant to strike the victim in the head, fracturing his skull. Some jurisdictions allow for even more flexibility in the definition of a deadly weapon. For example, Texas courts held in Stanul v. State that a floor could be considered a deadly weapon when the defendant slammed the victim’s head down upon it, and held in Turner v. State that hands and fists could be considered deadly weapons under certain circumstances.
A prosecutor charging a defendant with a crime such as "assault with a deadly weapon" must prove both that the defendant assaulted the victim with a weapon and that the weapon was indeed deadly. Whether or not a weapon was deadly is a question of fact usually left to the jury. The fact finder decides after examining the evidence presented and the facts of the case. The physical qualities of the weapon as well as the manner in which the defendant wielded it are important factors in the fact finder’s decision. Additionally, the size and weight of the weapon are often considered, as well the degree of force used by the defendant, and the type and bodily location of injuries to the victim.
Some jurisdictions recognize “deadly weapons per se” in their criminal statutes, meaning that the named weapon is considered likely to cause death regardless of the user’s intent or manner of use. Therefore, if a defendant used a weapon listed in the statute as deadly per se, the prosecution does not have to prove at trial that the weapon is deadly. Rather, the deadly nature of the weapon is automatically assumed. Firearms are the most common deadly weapons per se, but different jurisdictions may list other weapons. For example, Nebraska considers firearms, knives, and brass or iron knuckles as deadly weapons per se.
[Last updated in August of 2022 by the Wex Definitions Team]