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.

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

Word History and Origins

Origin of water rat¹

First recorded in 1545–55