qui vive

American  

[kee veev] / ki ˈviv /

1. who goes there? (used as a sentry's challenge)

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idioms

1. on the qui vive, on the alert; watchful.

   Special guards were on the qui vive for trespassers.

qui vive British  

/ ˌkiː ˈviːv /

noun

1. on the alert; attentive

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Etymology

Origin of qui vive

1720–30; < French: literally, (long) live who? (i.e., on whose side are you?)

Example Sentences

As the boats came close to a point on the bank a sentinel challenged, "Qui vive?"

From Canada by Bourinot, John George, Sir

Suddenly, down from the dark heights there came a challenge: "Qui vive?"

From Old Quebec The Fortress of New France by Bryan, Claude Glennon

Qui vive, kē vēv, Who goes there?—the challenge of French sentries to those who approach their posts.—Be on the qui vive, to be on the alert.

From Chambers's Twentieth Century Dictionary (part 3 of 4: N-R) by Various

"Don't talk Russian," said Dolokhov in a hurried whisper, and at that very moment they heard through the darkness the challenge: "Qui vive?" * and the click of a musket.

From War and Peace by Tolstoy, Leo, graf

The watchword is Qui vive? and the answer is L’état c’est moi—that was one of his favourite remarks, you know. 

From The Toys of Peace, and other papers by Saki