D defs.my
Entry 1 sense Webster, 1913

Qui vive

/(kē̇` vē̇v")/ · Qui· vive · IPA
01 The challenge of a French sentinel, or patrol; -- used like the English challenge: “Who comes there?”
  1. 1.
    The challenge of a French sentinel, or patrol; -- used like the English challenge: “Who comes there?”
Phrases & compounds
To be on the qui vive — to be on guard; to be watchful and alert, like a sentinel.