qui vive Meaning, Definition & Usage

  1. noun condition of heightened watchfulness or preparation for action
    alert.
    • bombers were put on alert during the crisis

WordNet

Qui` vive"
Etymology
F., fr. qui who + vive, pres. subj. of vivre to live.
Definitions
  1. The challenge of a French sentinel, or patrol; -- used like the English challenge: "Who comes there?"

Webster 1913