estoppel

Estoppel is a collective name given to a group of legal doctrines in common law legal systems whereby a person is prevented from asserting certain matters before the court to prevent injustice - the person is said to be "estopped". Estoppel may operate by way of preventing someone from asserting a particular fact in court, or exercising a certain right, or from bringing a particular claim. Black's Law Dictionary defines estoppel as a "bar or impediment raised by the law, which precludes a man from alleging or from denying a certain fact or state of facts, in consequence of his previous allegation or denial or conduct or admission, or in consequence of a final adjudication of the matter in a court of law."