keep one's eyes open

Idioms  

1. Also,. Be watchful and observant. For example, We should keep our eyes open for a change in the wind's direction, or Keep your eyes peeled for the teacher. The first phrase dates from the late 1800s; the second and third, both colloquial and alluding to the lids not covering the eyes, date from the mid-1800s and 1830s, respectively.

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Example Sentences

One had to keep one's eyes open there, for they were every bit as brave as we were.

From On the Pampas by Henty, G. A. (George Alfred)

From the snow-hut observatory, or even at a lesser distance, the Fram is invisible, and it is almost impossible to keep one’s eyes open, owing to the blinding snow.

From Farthest North Being the Record of a Voyage of Exploration of the Ship 'Fram' 1893-1896 by Nansen, Fridtjof

It is best to be serious and cautious, and to keep one’s eyes open, when one travels that way.

From Ainslee's, Vol. 15, No. 6, July 1905 by Various

There’s any amount of real misery to be met with in the neighbourhood of the Docks, ay, and all over London, for that matter, if one only chooses to keep one’s eyes open.

From The Pirate Island A Story of the South Pacific by Staniland, C.J.

There is something in the game of poker that will keep one's eyes open longer than will the fear of death, so the four kept on playing until time for luncheon.

From Tales of the Road by Crewdson, Charles N. (Charles Newman)