obligation

(noun) the social force that binds you to the courses of action demanded by that force. Synonyms: duty, responsibility. Examples: "We must instill a sense of duty in our children." "Every right implies a responsibility; every opportunity, an obligation; every possession, a duty"- john d.rockefeller jr."

(noun) the state of being obligated to do or pay something. Example: "He is under an obligation to finish the job."

(noun) a personal relation in which one is indebted for a service or favor. Synonyms: indebtedness.

(noun) a written promise to repay a debt. Synonyms: debt instrument, certificate of indebtedness.

(noun) a legal agreement specifying a payment or action and the penalty for failure to comply.