Definition
Leave and license is a defense to a civil action in trespass, asserting that the plaintiff consented to the defendant's entry onto the plaintiff's land or interference with the plaintiff's property or person. In other words, the defendant admits the act but argues it was not wrongful because the plaintiff gave permission—whether expressly or by conduct—for it to occur. Because trespass is an intentional tort requiring that the act be unauthorized, consent by the plaintiff negates the wrongfulness of the intrusion and defeats the claim entirely.
The phrase operates as a single legal concept: "leave" refers to the permission granted, and "license" refers to the legal authority conferred by that permission. Together they describe the defense that the plaintiff licensed the defendant's conduct and cannot now complain of it as a trespass.
Common Language
Modern common usage (Wiktionary): "Leave" means permission or consent to do something; "license" means a formal permit or grant of authority, or broader permission to act.
Historical common usage (Webster's 1913): "Leave" is defined as permission or liberty granted; "license" as authority or liberty given to do or forbear any act, particularly a formal permission from a constituted authority.
The common meanings of both words track closely to their legal meaning here, but the gap lies in how they operate together as a unified legal defense. In everyday speech, "leave and license" might suggest two separate grants of permission. In law, the phrase is a term of art describing a single affirmative defense—consent as a complete bar to trespass liability—not a procedural permission or regulatory authorization.
Common Confusion
Leave and license is sometimes confused with a general license to use property, as in property or contract law where a licensor grants ongoing rights. Those licenses create continuing legal relationships and enforceable interests. Leave and license, by contrast, is a retrospective defense—it looks back at a specific act already committed and argues that prior or contemporaneous consent made it lawful. A license in property law can be revoked prospectively; leave and license as a trespass defense either existed at the time of the act or it did not. The terms occupy different legal contexts and should not be conflated.
Why It Matters in Research
Researchers working with older common law pleading materials will encounter leave and license primarily in trespass actions predating modern notice pleading. In the era of common law forms of action, trespass was a precise writ, and affirmative defenses had to be formally pleaded. Leave and license was one of the recognized special pleas by which a defendant admitted the act and confessed it was done with consent.
In modern practice, the same doctrine survives as the consent defense to intentional torts—including trespass to land, trespass to chattels, battery, and related claims—but the phrase "leave and license" rarely appears in contemporary American pleadings. Researchers should expect to find the term in English common law authorities, 19th-century American treatises, and older reported decisions, but to find its functional equivalent described simply as "consent" in modern sources.
One research trap: because "license" in property law carries a distinct meaning (a revocable permission to enter land), historical sources sometimes blur the boundary between a property-law license and the leave and license defense. When reading older trespass cases, confirm whether the court is discussing a defense to liability or the existence of a property interest.
The defense also connects to the broader principle that volenti non fit injuria—a willing person suffers no wrong—which appears frequently in both tort and criminal law literature and may be the preferred framing in English sources.
Historical Dictionary Support
All three source dictionaries define leave and license identically: a defense to trespass setting up the plaintiff's consent. Black's (1st and 2nd editions) and Bouvier's agree without qualification. Bouvier cites Wharton's Law Lexicon, indicating the phrase had consistent usage across standard reference works of the period.
The uniformity of the definition across sources is notable but also limiting: none of the historical dictionaries elaborate on how consent must be established, whether it must be express or may be implied, or how the defense interacts with fraud or duress vitiating consent. These questions, which are legally significant, are left entirely to case law and treatise authority. Researchers should not expect doctrinal depth from the dictionary definitions alone.
Jurisdictional Note
Leave and license as a trespass defense is a common law doctrine recognized in all common law jurisdictions, but the phrase itself is more prevalent in English and older American authorities. Modern American jurisdictions address the same principle under the general heading of consent as an affirmative defense to intentional torts, governed by the Restatement (Second) of Torts framework.