Latin: In the civil law. An engagement or undertaking; particularly such as was made in the form of an answer to a formal interrogatory by the other party. Calvin. An engagement to pay a certain sum of money to the successful party in a cause. Calvin. Sponsio judicialis. In Roman law. A judicial wager corresponding; in some respects to the “feigned issue” of modern practice. Sponsio indiora. A trifling or ludicrous engagement, such as a court will not sustain an action for. 1 Karnes, Eq. Introd. 34. a informal undertaking, or one made without the usual formula of interrogation. Calvin.