n. The constraining power or authoritative character of a duty, a moral precept, a civil law, or a promise or contract voluntarily made; action upon the will by a sense of moral constraint.n. That to which one is bound; that which one is bound or obliged to do, especially by moral or legal claims; a duty.n. A claim; a ground of demanding.n. The state or fact of being bound or morally constrained by gratitude to requite benefits; moral indebtedness.n. In law: A bond containing a penalty, with a condition annexed, for payment of money, performance of covenants, or the like: sometimes styled a writing obligatory. By some modern English jurists the word is used as equivalent to legal duty generally.n. In Roman law, the juridical relation between two or more persons in virtue of which one can compel the other to do or not to do a certain act which has a monetary value, or can at least be measured by a monetary standard.n. In medieval schools, a rule of disputation by which the opponent was bound to admit any premise, not involving a contradiction, begging of the question, or other fallacy, which the respondent might propose.n. Synonyms Engagement, contract, agreement.