off guard

Idioms  

1. Also, off one's guard. Not watchful, easily surprised. It is often put as catch (or be caught) off guard, meaning “take (or be taken) by surprise.” For example, The securities analyst was caught off guard by that financial report, or With any luck the boss will be off guard when I come in late. [Late 1600s] The antonym, on guard or on one's guard, meaning “watchful or prepared, especially to defend oneself,” was first recorded in 1577. For example, In this crowd we must be on guard against pickpockets, or I'm always on my guard when I'm asked how I voted.

---

Example Sentences

I loved when a dish caught me off guard.

From Salon • Mar. 17, 2026

"We were taken off guard that it seemed to be working on time scales similar to that of silicon photodetectors."

From Science Daily • Mar. 4, 2026

The timing and scale of the conflict might have caught many off guard, Ebury’s head of market strategy Matthew Ryan said in a note.

From The Wall Street Journal • Mar. 2, 2026

He said residents were "completely caught off guard" on Sunday morning as news of El Mencho's capture, and the following unrest, broke.

From BBC • Feb. 23, 2026

She had not been caught off guard, thanks to Foremole.

From "Redwall" by Brian Jacques