An injunction is an order of a court requiring a person, corporation, or government entity to stop doing something and refrain from doing that thing in the future. In relatively rare cases, the court may issue a "mandatory injunction", compelling a person, company, or governmental unit take affirmative action to do something.

Injunctions historically are issued, only "when the remedy at law is inadequate". For example, suppose you own a home surrounded by 100 year old trees and your neighbor claims the trees are on his property and is planning on cutting them down. While the dispute is pending, the court might well issue an injunction preventing the neighbor from cutting down the trees until the matter is heard and completely resolved. Otherwise there could be irreparable harm to the land, money damages could not replace the trees, and the damages you would be entitled to could be speculative.

Another example of when an injunction may be issued is in the case of an ongoing course of conduct that violates your rights. For example, assume you own a Web site and another firm keeps on coming back and copying the material on your Web site in violation of copyright notices, no trespass notices, and contractual provisions. A court will issue an injunction to prevent that conduct from recurring. In fact, courts did exactly that to prevent others from improperly using portions of a site published by the creators of FreeAdvice.