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mouser

American  
[mou-zer] / ˈmaʊ zər /

noun

  1. an animal that catches mice: mouse.

    Our cat is a good mouser.

  2. a person or thing that seeks or prowls, as if for prey.

mouser British  
/ ˈmaʊsə, ˈmaʊzə /

noun

  1. a cat or other animal that is used to catch mice: usually qualified

    a good mouser
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of mouser

Middle English word dating back to 1350–1400; mouse, -er 1

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 Saturday came sad news that Palmerston, a black-and-white cat, once mouser to the Foreign Office and "Diplocat extraordinaire", had passed away in Bermuda where he retired in 2020.

From Barron's • Feb. 15, 2026

Palmerston, the former "chief mouser" of the Foreign Office, has died in Bermuda.

From BBC • Feb. 14, 2026

To me, he was the greatest cat ever, and the greatest mouser ever.

From Seattle Times • Jan. 13, 2023

He also developed an antagonistic relationship with the Foreign Office’s own mouser, Palmerston, who has since retired from public duty.

From New York Times • Sep. 6, 2022

Ralph shuddered at the thought of an electronic mouser sending his family screaming into the snow to freeze to death.

From "Ralph S. Mouse" by Beverly Cleary

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.