A waiver is the voluntary relinquishment or surrender of some right or privilege. While a waiver is often in writing, sometimes a person's actions can act as a waiver. An example of a written waiver is a disclaimer, which becomes a waiver when accepted.

In civil procedure, certain arguments must be raised in the first objection that a party submits to the court, or else they will be deemed waived.

In the case of Insurance Corp. of Ireland v. Compagnie des Bauxites de Guinee, 456 U.S. 694 (1982) the United States Supreme Court decided that when a court orders a party to produce proof on a certain point, and that party refuses to comply with the court's order, the court may deem that refusal to be a waiver of the right to contest that point, and assume that the proof would show whatever the opposing party claims that it would. In the case itself, the defendant had argued that the court lacked personal jurisdiction over it, but refused a court order to produce evidence of this lack of jurisdiction. The defendant argued the circular logic that, because the court lacked jurisdiction, the court had no authority to issue an order to show proof of the lack of jurisdiction. The Supreme Court rejected that argument, and determined that the defendant's refusal to comply waived the right to contest jurisdiction, just as if it had never contested jurisdiction at all.