do one's duty

do (one's) duty

1. To do, undertake, or accomplish that which is expected or required from one. I know it isn't easy facing off against the lowlifes of this town, but you're on the police force and you have to do your duty.2. To urinate or defecate, especially a house pet. I hate standing out here in the cold, waiting for the dog to do his duty.See also: duty

do one's duty

1. Do one's tasks or what is expected of one. For example, He was only doing his duty when he made the children finish their work. [Early 1500s] 2. Defecate or urinate, as in Please keep the dog outdoors until he does his duty. This euphemism for attending to such needs is heard less often today. [1930s] See also: duty