on duty

Idioms  

1. At one's post, at work, as in The new nurse was on duty that evening, or The watchman was fired because he was drunk on duty. [Mid-1600s] The antonym, off duty, means “not engaged in one's work,” as in Captain Smith was much more amiable when he was off duty. [Mid-1800s]

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Example Sentences

See Examples For:

on duty

Campus police had six officers on duty at the event, approximately one-quarter of the full force, and local police weren’t on site, according to court records.

From The Wall Street Journal ● Sep. 16, 2026

"You have to literally stay on duty and stare at the screen the whole time, because you can easily miss it," said Esko, who did not appear to struggle, even late into the night.

From Barron's ● Aug. 16, 2026

Witnesses I spoke with were unanimous on one detail: “Only one of the three officers on duty that night tried to do anything.”

From Slate ● Aug. 11, 2026

In the wake of PC Harper's death, Lissie Harper campaigned for harsher sentences for the manslaughter of emergency workers on duty.

From BBC ● Aug. 6, 2026

“Sleeping on duty? That’s disgraceful. They should fire that fellow.”

From "Hoot" by Carl Hiaasen