A suit in equity is a legal action where the plaintiff seeks an equitable remedy. A remedy is whatever the party to a lawsuit is asking for. Remedies fall into two general categories: legal and equitable. Historically, there were courts of law and courts of equity, and each handled different types of lawsuits. This is generally no longer the case in the U.S.; however, whether courts consider a remedy legal or equitable still depends on its historical classification.
Promissory estoppel is one type of suit in equity. Promissory estoppel constitutes a request to have the court make an otherwise nonbinding promise binding. A person may bring this type of suit in equity when something another person promised caused some type of harm. Generally, to prove promissory estoppel, the plaintiff must establish the defendant made a promise that he should have known would cause the plaintiff to do or refrain from doing something; the plaintiff reasonably relied on that promise to his detriment; and not enforcing the promise would produce an unjust outcome.
Temporary Restraining Order
A temporary restraining order is a suit in equity and also a type of injunction. Moreover, any type of lawsuit seeking injunctive relief constitutes a suit in equity. Injunctive relief is a request for the court to order someone to do or refrain from doing something. When a person requests a temporary restraining order, he may, for example, be asking the court to issue an order commanding another person stay a particular distance away from him.
A lawsuit requesting specific performance of a contract is also a type of suit in equity. When a plaintiff asks for specific performance, she is asking the court to make the defendant do what he contracted to do. Say, for example, a performer contracted with a theater to perform five shows but she performed only three. The theater could bring a suit in law requesting money damages. Or the theater could bring a suit in equity asking the court to order the singer to perform the remaining two shows.
Another type of suit in equity is a request for a constructive trust. Where the law is concerned, anything with the word "constructive" in it typically refers to something created by a court rather than the parties involved in the lawsuit. Accordingly, when a plaintiff asks the court for a constructive trust, he is asking the court to create a trust where one otherwise would not exist. A person requesting a constructive trust typically must prove, at minimum, that the person holding title to property would be unjustly enriched if he were allowed to keep the benefits associated with that property.