Ultra Vires Definition: Latin: without authority. Latin for without authority. A decision which is beyond the powers or authority of the person or organization which took it. When a decision is thought to be ultra vires, the typical remedy is to get a higher level judicial body, such as a Court, to assess and rule on it. If the decision has alreday been made, the remedy is certiorari. If the decision is anticipated, the remedy is prohibition. Categories & Topics: Civil Litigation & Evidence Law Dictionary Dictionary of Latin Law Terms Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!