Dictionary.com
Thesaurus.com
Synonyms

on the lookout

Idioms  

  1. Also, on the watch. Vigilant, alert, as in Be on the lookout for the twins—they're somewhere on this playground, or He was on the watch for her arrival. Both phrases were originally used with upon. Upon the lookout was originally nautical usage, meaning “on duty being watchful” (as for another ship, rocks, or land); it appeared in the mid-1700s, and on replaced upon about a century later. Upon the watch was first recorded in Daniel Defoe's Robinson Crusoe (1719), and on the watch in Jane Austen's Sense and Sensibility (1797).

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

On the lookout: A profusion of symptoms, and their sudden onset, are signs of flu in children.

From New York Times • Dec. 10, 2022

On the lookout for a black government SUV, Caputo and his lawyer were surprised when an FBI agent drove up in his personal car, a white Dodge Charger.

From Reuters • Mar. 22, 2019

On the lookout: Lawyers are circling around Santa Rosa’s burned-out neighborhoods.

From Los Angeles Times • Nov. 6, 2017

On the lookout for the next derivative-enhanced, subprime mortgage disaster, they keep missing opportunities.

From Washington Post • Jun. 17, 2016

On the lookout for the runaway priest, I take it.

From The Lost Treasure of Trevlyn A Story of the Days of the Gunpowder Plot by Everett-Green, Evelyn

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.