An injunction is an equitable remedy in the form of a special court order that compels a party to do or refrain from specific acts. "When a court employs the extraordinary remedy of injunction, it directs the conduct of a party, and does so with the backing of its full coercive powers." A party that fails to comply with an injunction faces criminal or civil penalties, including possible monetary sanctions and even imprisonment. They can also be charged with contempt of court.
The injunction is an equitable remedy, that is, a remedy that originated in the English courts of equity. Like other equitable remedies, it has traditionally been given when a wrong cannot be effectively remedied by an award of money damages. (The doctrine that reflects this is the requirement that an injunction can be given only when there is "no adequate remedy at law.") Injunctions are intended to make whole again someone whose rights have been violated. Nevertheless, when deciding whether to grant an injunction, courts also take into account the interests of non-parties (that is, the public interest). When deciding whether to give an injunction, and deciding what its scope should be, courts give special attention to questions of fairness and good faith. One manifestation of this is that injunctions are subject to equitable defenses, such as laches and unclean hands.
Injunctions are given in many different kinds of cases. They can prohibit future violations of the law, such as trespass to real property, infringement of a patent, or the violation of a constitutional right (e.g., the free exercise of religion). Or they can require the defendant to repair past violations of the law.
An injunction can require someone to do something, like clean up an oil spill or remove a spite fence. Or it can prohibit someone from doing something, like using an illegally obtained trade secret. An injunction that requires conduct is called a "mandatory injunction." An injunction that prohibits conduct is called a "prohibitory injunction.