something by which a person is bound or obliged to do certain things, and which arises out of a sense of duty or results from custom, law, etc.

something that is done or is to be done for such reasons

to fulfill one's obligations.

a binding promise, contract, sense of duty, etc.

the act of binding or obliging oneself by a promise, contract, etc.

Law .

an agreement enforceable by law, originally applied to promises under seal.

a document containing such an agreement.

a bond containing a penalty, with a condition annexed for payment of money, performance of covenants, etc.

any bond, note, bill, certificate, or the like, as of a government or a corporation, serving as evidence of indebtedness.

an indebtedness or amount of indebtedness.

a favor, service, or benefit for which gratitude is due.

a debt of gratitude

He felt an obligation to his teacher.

the state of being under a debt, as of gratitude, for a favor, service, or benefit.

noun

accountability , accountableness , agreement , bond , burden , business , call , cause , charge , chit * , commitment , committal , compulsion , conscience , constraint , contract , debit , debt , devoir , due bill , dues , duty , engagement , iou * , liability , must , necessity , need , occasion , onus , ought , part , place , promise , requirement , restraint , right , trust , understanding , imperative , responsibility , arrearage , arrears , due , indebtedness , covenant , encumbrance , guarantee , incumbency , loan , mortgage , noblesse oblige , oath , pledge , prevenance , stipulation , vow , warranty