These words are comparable in denoting that which one is bound to fulfil or perform. Obligation refers generally to anything that one is compelled to do, or to forbear from doing, by law, contract, promise, morality or the like. The word often implies immediate pressure to carry out, or to refrain from, a particular action: a legal obligation to serve in the armed forces. Duty is often used interchangeably with obligation , but the word more often refers to that which springs from an interior moral or ethical impulse rather than from external demands: he volunteered for the dangerous mission out of a sense of duty . Duty frequently has a more general reference than does obligation : to put duty before pleasure. And the word is applied to both a particular task and the general notion of work to be done: My duty is to check the inventory; duty before pleasure. Function refers to activity demanded by one’s position, profession or the like. It focuses on objective purpose, as discharged in the performance of particular duties : He mechanically performed the functions of a teacher but was uninspired. Office , as here considered, refers to the services, functions or duties connected with a position of trust.

• He swore to discharge faithfully the office of president; reconciled through the good offices of their clergyman.

Responsibility refers to any obligation , duty , function or office , for the fulfilment of which one may be called upon to answer to a particular person, the public in general or a Diving Being: it is the responsibility of the Commissioner of Police to maintain law and order.