obligation

the social force that binds you to the courses of action demanded by that force; "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

the state of being obligated to do or pay something; "he is under an obligation to finish the job"

a personal relation in which one is indebted for a service or favor

a written promise to repay a debt

a legal agreement specifying a payment or action and the penalty for failure to comply