Decisive Oath Law and Legal Definition

A decisive oath is an oath by a party in a lawsuit, used to decide the case because the party's adversary offered to refer the decision of the case to the party because s/he was not able to furnish adequate proof. A decisive oath is an oath upon which the cause is rested because one of the parties to the action defers or refers back to the other to decide the cause. A decisive oath is also termed as a decisory oath. .

The term is often seen used in civil law. A decisive oath may be used in any kind of civil contest. It may be used in questions of possession or of claim; and in personal and in real actions.