“Maxims are basically an established principle or proposition of law. These are universally admitted as being just and consonant with reason and are part of the general customs or common law of the land. The word is a variant of the Latin maxima, but this latter word is not found in extant texts of Roman law with any denotation exactly analogous to that of a legal maxim in the Medieval or modern definition, but the treatises of many of the Roman jurists on regular definitiones and sententiae iuris are to some degree collections of maxims. It is to be noted that most of the Latin maxims originate from the Medieval era in European states which used Latin as their legal language.
- Actus Reus: a guilty act
The prohibited conduct or behaviour that the law seeks to prevent. Although commonly referred to as the “guilty act” this is rather simplistic, as the actus reus includes all the aspects of the crime except the accused’s mental state (mens rea). In most cases the actus reus will simply be an act (e.g.appropriation of property is the act of theft) accompanied by specified circumstances (e.g. that the property belongs to another). Sometimes, however, the actus reus may be an omission to act (e.g. failure to prevent death may be the actus reus of manslaughter : R v. Stone and Dobinson  QB 354) or it may include a specified consequence (death resulting being the consequence required for the actus reus of murder or manslaughter). In certain cases the actus reus may simply be a state of affairs rather than an act (Winzar v Chief Constable of Kent (1983) The Times 28 March 1983).
- Ad litem: As regards the action
A grant ad litem is the appointment by a court of a person to act on behalf of an estate in court proceedings, when the estate’s proper representatives are unable or unwilling to act. A guardian ad litem is the former name for a litigation friend responsible for the conduct of legal proceedings on behalf of someone else.
- Amicus curiae: Friend of the court or tribunal
A non-party who gives evidence before the court so as to assist it with research, argument, or submissions. For example, in the House of Lords decision on whether to allow the extradition of General Pinochet their lordships sought an independent expert opinion on the matter of diplomatic immunity. For that purpose they called upon an expert in this field, David Lloyd Jones QC, to assist the court.
- Caveat emptor: Let the buyer beware
It is a common law maxim warning a purchaser that he could not claim that his purchases were defective unless he protected himself by obtaining express guarantees from the vendor. The maxim has been modified by statute: under the Sale of Goods Act 1979 (a consolidating statute), contracts for the sale of goods have implied terms requiring the goods to correspond with their description and any sample and, if they are sold in the course of a business, to be of satisfactory quality and fit for any purpose made known to the seller.
- Doli incapax: Incapable of wrong
A child under the age of 10 is deemed incapable of committing any crime. Above the age of 10 children are doli capax and are treated as adults, although they will usually be tried in special youth courts (with the exception of homicide and certain other grave offences) and subject to special punishments.
- Ex parte:
i) On the part of one side only–An ex parte hearing is defined in Criminal Procedure Rules as a hearing where only one party is allowed to attend and make submissions. However, the term ex parte is no longer generally used in civil proceedings, having been replaced by the phrase without notice.
ii) On behalf of–This term is used in the headings of law reports together with the name of the person making the application to the court in the case in question, e.g. in applications for judicial review.
- Ex post facto: Out of the aftermath, or After the fact.
It is a law that retroactively changes the legal consequences (or status) of actions that were committed, or relationships that existed, before the enactment of the law. In criminal law, it may criminalise actions that were legal when committed; it may aggravate a crime by bringing it into a more severe category than it was in when it was committed; it may change the punishment prescribed for a crime, as by adding new penalties or extending sentences; or it may alter the rules of evidence in order to make conviction for a crime likelier than it would have been when the deed was committed.
- Habeas Corpus: You have the body.
A writ (court order) that commands an individual or a government official who has restrained another to produce the prisoner at a designated time and place so that the court can determine the legality of custody and decide whether to order the prisoner’s release.
Significant case relating to it is Purshottam Govindji Halaivas. Shree B.M.Desai, Additional Collector of Bombay and Ors.vs Paul Manickam
- In camera: In the chamber, In private.
A court hearing must usually be public but the public may be barred from the court or the hearing may continue in the judge’s private room in certain circumstances; e.g., when it is necessary in the interests of national security or to protect the identity of a witness unwilling to give evidence in public. Part 39 of the Civil Procedure Rules and Part 16 of the Criminal Procedure Rules deal within camera hearings.
- Ignorantia juris non excusat: Ignorance of the law excuses no one.
In other words, A person who is unaware of a law may not escape liability for violating that law merely because one was unaware of its content.
- In rem: Against the thing
i) Describing a right that should be respected by other people generally, such as ownership of property, as distinct from a right in personam.
ii) Describing a court action that is directed against an item of property, rather than against a person or group of people. Actions in rem are a feature of the Admiralty Court.
- Jus Necessitatis– It means a person’s right to do what is required for which no threat of legal punishment is a dissuasion.
Dissuasion here means the action or process of trying to persuade someone not to take a particular course of action. This maxim is called the doctrine of necessity. It means a person doing a thing under compulsion of situation. It is not considered a wrongful act. It comes under the ambit of section 81 of IPC.
- Malum prohibitum: In a way opposite of Malum in se.
It means ‘Crimes are criminal not because they are inherently bad, but because the act is prohibited by the law of the state.’ e.g., Jurisdiction in India requires drivers to drive on the left side of the road. This is not because driving on the right side of a road is considered immoral, but because the law says to drive on the left side and not on the right side.
- Mandamus: A writ or order that is issued from a court of superior jurisdiction that commands an inferior tribunal/court to perform, or refrain from performing, a particular act, the performance of which is required by law as an obligation.
Significant case relating to it is Shenoy and Co., Bangalore and Ors. Vs Commercial Tax Officer, Circle II, Bangalore and Ors. (AIR 1985 SC 621)
- Obiter dictum: Things said by the way.
It is generally used in law to refer to an opinion or non-necessary remark made by a judge. It does not act as a precedent. In other words, Obiter dictum means “that which is said in passing,” an incidental statement. Specifically, in law, it refers to a passage in a judicial opinion which is not necessary for the decision of the case before the court. Such statements lack the force of precedent but may nevertheless be significant.
- Qui facit per alium, facit per se: He who acts through another acts himself.
In simple words, It is a fundamental legal maxim of the law of agency. It is a maxim often stated in discussing the liability of the employer for the act of employee in terms of vicarious (indirect, secondhand) liability. It says that person who does a thing through the instrumentality of another, is held as having done it himself. e.g., that an employer is liable for the consequences of any act done by employees in the ordinary course of their duties and responsibilities.
- Res ipsa loquitur: The thing speaks for itself
A principle often applied in the tort of negligence. If an accident has occurred of a kind that usually only happens if someone has been negligent, and the state of affairs that produced the accident was under the control of the defendant, it may be presumed in the absence of evidence that the accident was caused by the defendant’s negligence (Scott v London and St Katherine Docks Co(1865) 3 Hurl. & C. 596).
- Ubi Jus Ibi Remedium : There is no wrong without a remedy. Wherever there is a right there is a remedy.
Significant case relating to it is Kalpana Yog`esh Dhagat Vs. Reliance Industries Limited
- Ultra vires: Beyond the powers
Describing an act by a public authority, company, or other body that goes beyond the limits of the powers conferred on it. Ultra vires acts are invalid. The ultra vires doctrine applies to all powers, whether created by statute or by a private document or agreement (such as a trust deed or contract of agency). In the field of public (especially administrative) law it governs the validity of all delegated and sub-delegated legislation. This is ultra vires not only if it contains provisions not authorized by the enabling power but also if it does not comply with any procedural requirements regulating the exercise of the power. The doctrine also governs the validity of decisions made by inferior courts or administrative or domestic tribunals and the validity of the exercise of any administrative power. The decision of a court or tribunal is ultra vires if it exceeds jurisdiction, contravenes procedural requirements, or disregards the rules of natural justice (the power conferring jurisdiction being construed as requiring the observance of these). The exercise of an administrative power is ultra vires not only if unauthorized in substance, but equally if (for example) it is procedurally irregular, improperly motivated, or in breach of the rules of natural justice (substantive vs. Procedural ultra vires). The remedies available for this second aspect of the doctrine are quashing orders, prohibiting orders, declaration, and injunction.
- Volenti non fit injuria: Damage suffered by consent gives no cause of action.
In other words, If someone willingly places himself in a position where he knows that harm might result, then he is not able (allowed) to bring a claim against the other party in tort or delict (a violation of the law).The defence that the claimant consented to the injury or (more usually) to the risk of being injured. Knowledge of the risk of injury is not sufficient; there must also be (even if only by implication) full and free consent to bear the risk (Simms v Leigh Rugby Football Club Ltd  2 All ER 923).