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

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)

It is but a small affair to ride alone, but in the confusion of such a train, in a short trot on a lively beast, one must keep one's eyes open.

From The German Classics of the Nineteenth and Twentieth Centuries, Volume 10 Prince Otto Von Bismarck, Count Helmuth Von Moltke, Ferdinand Lassalle by Francke, Kuno

“A very good school, I should say, Embleton; one has to keep one’s eyes open there.”

From With Cochrane the Dauntless by Henty, G. A. (George Alfred)

Thou knowest well how to furnish a guard-room when one is required to keep one's eyes open and one's spirits up.

From King Eric and the Outlaws, Vol. 1 or, the Throne, the Church, and the People in the Thirteenth Century. Vol. I. by Ingemann, Bernhard Severin

One cannot keep one's eyes open very long without winking, but the stranger did.

From The Ape, the Idiot & Other People by Morrow, W. C.