Vigilant; alert; watching carefully for something.
Examples:
- Be on the lookout for the twins—they're somewhere on this playground.
Origin: Mid-1700s (nautical); 'on' replaced 'upon' about a century later
Synonyms: on the watch
Vigilant; alert; watching carefully for something.
Examples:
Origin: Mid-1700s (nautical); 'on' replaced 'upon' about a century later
Synonyms: on the watch