Latin Maxims on ExcellentWiki - Legal Encyclopedia

Actus Reus

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Actus reus (Latin: “guilty act”) is the physical element of a crime. It refers to the external conduct, omission, or state of affairs that the law prohibits. Together with mens rea (the mental element), actus reus forms one of the two essential components of criminal liability. The maxim actus non facit reum nisi mens sit rea—an act does not make a person guilty unless the mind is guilty—captures the principle that both elements must coincide.

Mens Rea

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Mens rea (Latin: “guilty mind”) is the mental element of a crime—the state of mind that the prosecution must prove the defendant had at the time of the prohibited conduct. It is the principle that criminal liability requires fault, distinguishing criminal punishment from strict liability or mere accident. The foundational maxim actus non facit reum nisi mens sit rea embodies this requirement: an act does not make a person guilty unless the mind is guilty.

Habeas Corpus

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Habeas corpus (Latin: “you shall have the body”) is a legal writ requiring a person who has detained another to bring the detained person before a court to justify the detention. It is the primary procedural mechanism for challenging unlawful imprisonment. The full phrase—habeas corpus ad subjiciendum—requires the custodian to “produce the body” for judicial examination.

Habeas corpus serves as the great writ of liberty, protecting individual freedom against arbitrary state detention. It ensures that no person is imprisoned without legal justification and that every detainee has access to a court to challenge the lawfulness of their detention. The writ embodies the principle that liberty is the default and detention requires lawful authority.

Caveat Emptor

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Caveat emptor (Latin: “let the buyer beware”) is a common law doctrine providing that the buyer of goods purchases them at their own risk regarding quality and condition, unless the seller has given an express warranty or the seller has committed fraud. The maxim places the burden of inspection and due diligence on the purchaser. The buyer has no automatic right to a refund or replacement simply because the goods are defective.

Nemo Dat Quod Non Habet

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Nemo dat quod non habet (Latin: “no one can give what they do not have”) is a fundamental principle of property law providing that a person cannot transfer better title to property than they themselves possess. If a seller has defective title, the buyer acquires equally defective title—or none at all. The rule protects ownership rights by ensuring that a thief, a finder, or any person with limited interest cannot pass good title to a third party.

Res Judicata

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Res judicata (Latin: “a matter judged”) is the doctrine that a final judgment rendered by a competent court on the merits is conclusive between the parties and their privies, barring subsequent litigation of the same claim or issue. It serves the interests of finality, repose, and judicial economy. The maxim interest rei publicae ut sit finis litium—it is in the public interest that litigation come to an end—is its policy foundation.

Stare Decisis

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Stare decisis—the abbreviation of stare decisis et non quieta movere (Latin: “stand by things decided and do not disturb settled matters”)—is the legal doctrine that courts should follow previously decided cases when ruling on substantially similar facts and legal issues. It is the foundation of the common law system, providing predictability, consistency, and equality before the law.

The doctrine rests on the principle that like cases should be decided alike. This requirement of formal justice is fundamental to the rule of law. When courts follow precedent, they provide notice to individuals about their legal rights and obligations, enable reliance on settled law, and constrain judicial discretion within principled boundaries.

Prima Facie

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Prima facie (Latin: “at first sight” or “on first appearance”) describes evidence that is sufficient to establish a fact or case unless rebutted. A prima facie case is one that, if unrebutted, would entitle the party presenting it to a judgment in their favor. The term is used in evidence law, criminal procedure, tort law, and legal ethics to denote the initial threshold of proof that shifts the burden of production to the opposing party.

Bona Fide

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Bona fide (Latin: “in good faith”) describes conduct that is honest, sincere, and without fraud or deception. It is a fundamental principle across multiple areas of law, requiring parties to act with honesty of intention and fair dealing. Bona fides is the opposite of mala fides (bad faith). The related concept of bona fide purchaser—one who acquires property for value, without notice of any defect in the seller’s title—receives special legal protection.

Ultra Vires

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Ultra vires (Latin: “beyond the powers”) describes an act performed without legal authority. Acts within one’s power are intra vires. The ultra vires doctrine applies in multiple legal contexts: corporate law (a corporation acting beyond its chartered objects), administrative law (a government agency exceeding its statutory authority), and constitutional law (a government exceeding constitutional limits). Acts found to be ultra vires are void or voidable.

The ultra vires doctrine ensures that legal actors—whether corporations, government agencies, or constitutional bodies—operate within the limits of their authority. It is a mechanism of accountability, preventing the exercise of power beyond lawful boundaries. The doctrine reflects the principle that legal authority is limited and that those who exercise it must stay within prescribed bounds.

Volenti Non Fit Injuria

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Volenti non fit injuria (Latin: “to one who is willing, no harm is done”) is a common law defense providing that a person who voluntarily consents to a risk of injury cannot later recover damages for that injury. The principle reflects the idea that consent negates the legal wrong: nulla iniuria est, quae in volentem fiat—no wrong is done to one who consents.

Volenti is a complete defense: if established, the plaintiff recovers nothing, regardless of the defendant’s negligence. This distinguishes it from contributory negligence, which merely reduces damages proportionally. The defense embodies the principle of individual autonomy: those who freely choose to accept risks should bear the consequences of their choice.

Ratio Decidendi

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Ratio decidendi (Latin: “the reason for the decision”) is the principle or rule of law upon which a court’s decision is founded. It is the binding part of a judicial decision, distinguished from obiter dicta—matters said in passing that are persuasive but not binding. Identifying the ratio decidendi is essential to the doctrine of precedent: it is the ratio that later courts must follow under stare decisis.

The ratio decidendi is the legal principle necessary to reach the court’s conclusion on the facts presented. It is the rule that connects the material facts to the outcome. Every judicial decision contains at least one ratio—the principle without which the case would have been decided differently. The ratio is the contribution the case makes to the body of law.

Obiter Dictum

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Obiter dictum (Latin: “a thing said in passing”; plural: obiter dicta) is a remark, observation, or opinion expressed by a judge in a judicial decision that is not essential to the resolution of the case. Unlike the ratio decidendi, obiter dicta are not binding on later courts. However, obiter statements from authoritative courts carry persuasive weight and may influence subsequent judicial development.

The distinction between ratio and obiter is fundamental to the doctrine of precedent. The ratio is the binding principle; obiter is commentary. Identifying whether a statement is ratio or obiter requires determining whether it was necessary to the decision. Statements that go beyond what is needed to decide the case are obiter.

Ex Post Facto

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Ex post facto (Latin: “after the fact”) refers to laws that retroactively criminalize conduct that was legal when performed, increase punishment for past offenses, or alter procedural rules to the disadvantage of defendants. Ex post facto laws are generally prohibited in constitutional democracies as a violation of fundamental fairness and the rule of law. The maxim nullum crimen sine lege, nulla poena sine lege—no crime without law, no punishment without law—embodies this prohibition.

Sub Judice

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Sub judice (Latin: “under judgment”) describes a matter that is currently under judicial consideration and not yet finally determined. The term identifies cases pending before a court, during which certain restrictions may apply to public discussion—particularly in the media—to prevent prejudice to the proceedings. The principle protects the right to a fair trial by limiting extra-judicial commentary that could influence the court, parties, witnesses, or jurors.

The sub judice principle reflects the tension between two fundamental values: the right to a fair trial and freedom of expression. Unrestricted comment on pending cases can prejudice proceedings by influencing jurors, intimidating witnesses, or pressuring judges. At the same time, free expression includes the right to comment on matters of public interest, including litigation.

De Novo

Sun, 05 Jul 2026 00:00:00 +0000

Definition

De novo (Latin: “from the beginning” or “anew”) describes a standard of review in which an appellate court considers a matter as if for the first time, giving no deference to the lower court’s conclusions. In de novo review, the appellate court independently determines the correct legal rule and applies it to the facts. It is the most searching standard of appellate review, applied primarily to questions of law.

In Rem

Sun, 05 Jul 2026 00:00:00 +0000

Definition

In rem (Latin: “against a thing”) describes legal proceedings or jurisdictional authority directed against property rather than against a specific person (in personam). An in rem action determines the status or ownership of property, and the court’s judgment binds all persons claiming an interest in that property. Admiralty, forfeiture, probate, and property registration are typical in rem proceedings.

The distinction between in rem and in personam actions is fundamental to procedural law. In personam actions impose personal liability on the defendant; in rem actions determine interests in specific property. In personam judgments may be enforced against any assets of the defendant; in rem judgments are limited to the specific property.

Inter Alia

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Inter alia (Latin: “among other things”) is a legal term used to indicate that a list, illustration, or example is not exhaustive. It signals that the item mentioned is one of several, not the only one. The phrase appears frequently in statutes, contracts, pleadings, judgments, and legal writing to avoid the implication that a particular item is exclusive.

The phrase is a form of the Latin preposition inter (among) combined with alia (other things, neuter plural). Inter alios is the masculine plural form used when referring to persons, though inter alia is more commonly used as a general phrase. Proper Latin usage distinguishes the gender of the items referred to, but in modern legal English, inter alia has become a fixed expression.

Per Curiam

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Per curiam (Latin: “by the court”) is an opinion delivered by an appellate court as a whole, rather than being attributed to a specific judge. Per curiam opinions are issued on behalf of the court collectively, reflecting the agreement of all participating judges. They are typically used for unanimous decisions on straightforward issues where the reasoning does not warrant individual attribution.

The per curiam form emphasizes that the decision is the court’s institutional judgment rather than any individual judge’s personal view. It signals that the decision was unanimous and that the court speaks with one voice. The lack of individual attribution reinforces the collective nature of appellate decision-making.

Certiorari

Sun, 05 Jul 2026 00:00:00 +0000

Definition

Certiorari (Latin: “to be informed of” or “to be made certain in regard to”) is a writ or discretionary process by which a higher court reviews the decision of a lower court, tribunal, or administrative body. In modern practice, it is most commonly associated with the U.S. Supreme Court’s discretionary jurisdiction: the Court grants writs of certiorari to review cases of national importance.

The term derives from the original Latin writ commanding lower officials to certify records for review. The writ commanded the lower court to “certify” the record of proceedings so that the higher court could examine them. This historical origin is reflected in the modern phrase “granting certiorari” or simply “granting cert.”