A lawsuit is a civil action brought before a court in which the party commencing the action, the plaintiff, seeks a legal remedy. If the plaintiff is successful, judgment will be given in the plaintiff's favour, and a range of court orders may be issued to enforce a right, impose a penalty, award damages, impose an injunction to prevent an act or compel an act, or to obtain a declaratory judgment to prevent future legal disputes.
It usually involves dispute resolution of private law issues between individuals, business entities or non-profit organizations. However, it may involve public law issues in those jurisdictions that enable the government to be treated as if it were a private party in a lawsuit (as plaintiff or defendant regarding an injury), or that provide the government with a civil cause of action to enforce certain laws rather than criminal prosecution. The conduct of a lawsuit is called litigation.
Though the vast majority of lawsuits are settled easily and never even get to trial, they can expand into a very complicated process. This is particularly true in federal systems, where a federal court may be applying state law (e.g., the Erie doctrine in the United States) or vice versa, or one state applying the law of another, and where it additionally may not be clear which level (or location) of court actually has jurisdiction over the claim or personal jurisdiction over the defendant. Domestic courts are also often called upon to apply foreign law, or to act upon foreign defendants, over whom they may not, as a practical matter, even have the ability to enforce a judgment if the defendant's assets are outside their reach.
Lawsuits become additionally complicated as more parties become involved (see joinder). Within a "single" lawsuit, there can be any number of claims and defenses (all based on numerous laws) between any number of plaintiffs or defendants, who each can bring any number of cross-claims and counterclaims against each other, and even bring additional parties into the suit on either side after it progresses. However, courts typically have some power to separate out claims and parties into separate suits if it is more efficient to do so, such as if there is not a sufficient overlap of factual issues between the various claims.
Within the time limit, the defendant may choose to file an answer raising all defenses and denying the plaintiff's allegations. Filing an answer "joins the cause" and moves the case into the pretrial phase. In the alternative, the defendant can dispute the validity of the complaint by filing one or more "pre-answer" motion to dismiss. If all such motions are denied by the trial court, and the defendant loses on all appeals from such denials (if that option is available), then the defendant must file an answer.
Usually the pleadings are drafted by a lawyer, but in many courts a person can file papers and represent themselves, which is called appearing pro se. Many courts have a pro se clerk to assist people without lawyers.
At the close of discovery, the parties may pick a jury and then have a trial by jury. Or, the case may proceed as a bench trial heard only by the judge, if the parties waive a jury trial, or if the right to a jury trial is not guaranteed for their particular claim (such as those under equity in the U.S.) or for any lawsuits within their jurisdiction.
There are numerous motions that either party can file throughout the lawsuit to terminate it "prematurely" — before submission to the judge or jury for final consideration. These motions attempt to persuade the judge, through legal argument and sometimes accompanying evidence, that because there is no reasonable way that the other party could legally win, there is no sense in continuing with the trial. Motions for summary judgment, for example, can usually be brought before, after, or during the actual presentation of the case. Motions can also be brought after the close of a trial to undo a jury verdict that is contrary to law or against the weight of the evidence, or to convince the judge that he should change his decision or grant a new trial.
Also, at any time during this process from the filing of the complaint to the final judgment, the plaintiff may withdraw his complaint and end the whole matter, or the defendant may agree to a settlement, which involves a negotiated award followed also by the plaintiff withdrawing his complaint and the settlement entered into the court record.
If the judgment is for the plaintiff, then the defendant must comply under penalty of law with the judgment, which will usually be a monetary award. If the defendant fails to pay, the court has various powers to seize any of the defendant's assets located within its jurisdiction. If all assets are located elsewhere, the plaintiff must file another suit in the appropriate court to seek enforcement of the other court's previous judgment. This can be a difficult task when crossing from a court in one state or nation to another, though courts tend to grant each other respect when there is not a clear legal rule to the contrary. A defendant who has no assets in any jurisdiction is said to be "judgment-proof." In most cases, nothing can be done to collect an award from a moneyless defendant.
Indigent judgment-proof defendants are no longer imprisoned; debtor's prisons have been outlawed by statute, constitutional amendment, or international human rights treaties in the vast majority of common law jurisdictions.
In England and Wales the term "claim" is far more common; the person initiating proceedings is called the claimant.
American terminology is slightly different, in that the term "claim" refers only to a particular count (or cause of action) in a lawsuit. Americans also use "claim" to describe a demand filed with an insurer or administrative agency. If the claim is denied, then the claimant (or policyholder or applicant) files a lawsuit with the courts and becomes a plaintiff.
In medieval times, both "action" and "suit" had the approximate meaning of some kind of legal proceeding, but an action terminated when a judgment was rendered, while a suit also included the execution of the judgment.