Dictionary.com
definitions

water rat

noun
  1. any of various rodents having aquatic habits.
  2. the muskrat, Ondatra zibethica.
  3. (in Australia and New Guinea) any of the aquatic rats of the subfamily Hydromyinae, especially of the genus Hydromys.
  4. Slang. a vagrant or thief who frequents a waterfront.

Origin of water rat

First recorded in 1545–55
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for water rat

Historical Examples of water rat

  • Think of living so near a beaver or a water-rat with clothes on!

    Malbone

    Thomas Wentworth Higginson

  • The water-rat came from a hole five feet above the river-level.

  • “The only offensive thing I have is a pair of incisors,” said the water-rat.

  • Ray says, and Linnæus after him, that the water-rat is web-footed behind.

  • Indeed he had been known among his playmates in the old country as the “Water-rat.”

    The Buffalo Runners

    R.M. Ballantyne

British Dictionary definitions for water rat

water rat

noun
  1. any of several small amphibious rodents, esp the water vole or the muskrat
  2. any of various amphibious rats of the subfamily Hydromyinae, of New Guinea, the Philippines, and Australia
  3. informal a person who is very fond of water sports
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