active duty

American  

noun

Military.

1. the status of full-time service.

   on active duty.

---

active duty Idioms  

1. Full-time service, as in Julian is 81, but he still comes to the office every day and is very much on active duty. This term comes from the military, where it stands in opposition to reserve, which refers to troops still in the military but not actively engaged. It is occasionally transferred to civilian matters as well. [First half of 1800s]

---

Example Sentences

The US has more than 36,000 active duty troops in Germany.

From BBC • May 3, 2026

LONDON—In 2001, Prince Andrew retired from active duty in the Royal Navy, with a reputation as a war hero and something of a playboy.

From The Wall Street Journal • Feb. 21, 2026

Kelly could even be recalled to active duty, then court-martialed, an act that would remove his military status entirely and even land the senator in prison.

From Slate • Jan. 13, 2026

The players only play for the love of the game, graduate, then go on to active duty in the armed forces for a minimum of five years.

From Los Angeles Times • Jan. 10, 2026

All the officers had reported for active duty, leaving the two of them behind at Riverbank, with less and less military code breaking coming their way.

From "The Woman All Spies Fear" by Amy Butler Greenfield