rat

[ rat ]
See synonyms for: ratrattedratting on Thesaurus.com

noun
  1. any of several long-tailed rodents of the family Muridae, of the genus Rattus and related genera, distinguished from the mouse by being larger.

  2. any of various mammals similar to or related to the long-tailed rodents of the genus Rattus.

  1. Slang. a scoundrel.

  2. Slang.

    • a person who abandons or betrays their party or associates, especially in a time of trouble.

    • a scab laborer.

  3. Slang. a person who frequents a specified place: a mall rat;gym rats.

  4. a pad with tapered ends formerly used in women's hairstyles to give the appearance of greater thickness.

interjection
  1. rats, Slang. (an exclamation of disappointment, disgust, or disbelief.)

verb (used without object),rat·ted, rat·ting.
  1. Slang.

    • to desert one's party or associates, especially in a time of trouble.

    • to turn informer; squeal: He ratted on the gang, and the police arrested them.

    • to work as a scab.

  2. to hunt or catch rats.

verb (used with object),rat·ted, rat·ting.
  1. to make (the hair) appear thicker by use of a small pad of material or by teasing.

Verb Phrases
  1. rat out, Slang. to inform on: He ratted out his partners in exchange for a lighter sentence.

Idioms about rat

  1. smell a rat, to suspect or surmise treachery; have suspicion: After noting several discrepancies in his client's story, the attorney began to smell a rat.

Origin of rat

1
First recorded before 1000; Middle English rat(t)te, Old English ræt; cognate with Dutch rat, German Ratz, Ratte

Other words from rat

  • rat·like, adjective

Words Nearby rat

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use rat in a sentence

British Dictionary definitions for rat

rat

/ (ræt) /


noun
  1. any of numerous long-tailed murine rodents, esp of the genus Rattus, that are similar to but larger than mice and are now distributed all over the world: See also brown rat, black rat

  2. informal a person who deserts his or her friends or associates, esp in time of trouble

  1. informal a worker who works during a strike; blackleg; scab

  2. slang, mainly US an informer; stool pigeon

  3. informal a despicable person

  4. smell a rat to detect something suspicious

verbrats, ratting or ratted
  1. (intr usually foll by on) informal

    • to divulge secret information (about); betray the trust (of)

    • to default (on); abandon: he ratted on the project at the last minute

  2. to hunt and kill rats

Origin of rat

1
Old English rætt; related to Old Saxon ratta, Old High German rato

Derived forms of rat

  • ratlike, adjective

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

Other Idioms and Phrases with rat

rat

In addition to the idioms beginning with rat

  • rat on
  • rat race

also see:

  • like a drowned rat
  • smell a rat

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