Lawsuit

A lawsuit is a civil court proceeding where one or more parties, called the plaintiff or claimant, bring a case against one or more other parties, known as the defendant. The archaic phrase "suit in law" appears in only a few current laws. In a lawsuit, the plaintiff claims to have suffered a loss due to the defendant’s actions and asks the court for a legal or equitable remedy. The defendant must respond to the plaintiff’s complaint or risk a default judgment. If the plaintiff wins, the court enters judgment in their favor and may grant remedies such as damages, restitution, or an injunction to prevent or compel an action. A declaratory judgment may also be issued to avoid future disputes.

Lawsuits can resolve private law disputes between individuals, businesses, or nonprofits. They can also involve public law when the state acts as a private party—either as a plaintiff enforcing laws or as a defendant contesting the legality of its own laws or seeking damages for harm caused by its agents. Conducting a civil action is called litigation. The parties are litigants, and their attorneys are litigators. The term litigation can also refer to criminal actions.

The word "lawsuit" combines "law" and "suit." "Suit" comes from Old French "suite" or "sieute," meaning to pursue or follow, which traces to Latin "secutus," the past participle of "sequi" (to attend or follow). Similarly, "sue" derives from Old French "suir" or "sivre," also meaning to pursue, from Latin "sequi."

Rules of criminal or civil procedure govern lawsuits in the common law adversarial system. These rules come from statutes, case law, and constitutional provisions like due process. Procedural details vary greatly by jurisdiction and even by court within the same jurisdiction. Litigants must know these rules or hire competent counsel, as they control the lawsuit’s timing and progression. Failure to follow procedural rules can limit a party’s ability to present claims or defenses, or even lead to dismissal.

Although most lawsuits settle before trial, they can be complex, especially in federal systems where a federal court applies state law (e.g., the Erie doctrine in the United States) or vice versa. One state may also apply another state’s law, and it may be unclear which court has jurisdiction over the claim, personal jurisdiction over the defendant, or whether the plaintiff has standing. About 98 percent of U.S. federal civil cases resolve without trial. Domestic courts may also apply foreign law or act against foreign defendants, but may lack the ability to enforce a judgment if the defendant’s assets are outside their reach.

Lawsuits grow more complicated with more parties (see joinder). A single lawsuit can involve many claims and defenses between numerous plaintiffs or defendants, including cross-claims and counterclaims, and new parties can be added later. However, courts can sever claims or parties into separate actions for efficiency if factual issues do not sufficiently overlap.

The official ruling of a lawsuit can be misleading, as post-ruling outcomes are often not listed online. For example, in *William J. Ralph Jr. v. Lind-Waldock & Company* (September 1999), one might assume Ralph lost, but evidence later showed improper activity by Lind-Waldock, and Ralph settled. This highlights the need for comprehensive information beyond internet searches when researching legal decisions.

In a common law jurisdiction, a lawsuit generally proceeds as follows:

**Pleading** A lawsuit begins when a complaint or petition, called a pleading, is filed with the court. The complaint must state that one or more plaintiffs seek damages or equitable relief from one or more defendants and include the relevant factual basis.