Obligation,  【duty】  are comparable when they denote what a person is bound to do or refrain from doing or for the performance or nonperformance of which he is held responsible.

In ordinary usage obligation typically implies immediate constraint and a specific reference.

【Duty】 , on the other hand, often suggests less compulsion from immediate circumstances but a greater impulsion on moral or ethical grounds; thus, a person weighed down by a sense of  【duty】  is keenly aware of what in general he ought to do; one has a sense of obligation only in a particular case and for a particular reason.

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