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

A guard is on duty, cars are in the parking lot and lights on.

From Los Angeles Times ● Oct. 21, 2026

An Li, a PhD student at Beijing Normal University and the Transient Advocate for EP, was on duty when the signal appeared.

From Science Daily ● Oct. 8, 2026

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

It said an inexperienced third officer was at the helm and there was no lookout on duty, describing it as "serious negligence".

From Barron's ● Sep. 3, 2026

Max sits us all in a circle in the living room—except for Siunek, who is on duty at the window—and I’m reminded of a pack of snarling dogs.

From "The Light in Hidden Places" by Sharon Cameron

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