rat

[ rat ]

/ ræt /

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See synonyms for: rat / ratted / ratting on Thesaurus.com

noun

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

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

Slang. a scoundrel.

Slang.

a person who abandons or betrays their party or associates, especially in a time of trouble.
an informer.
a scab laborer.

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

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

interjection

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

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

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.

to hunt or catch rats.

verb (used with object), rat·ted, rat·ting.

to make (the hair) appear thicker by use of a small pad of material or by teasing.

Verb Phrases

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

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Idioms about rat

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

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

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use rat in a sentence

In one study from 2006, surgical residents learning to splice tiny blood vessels in rats were trained in either a spaced sequence — one session a week, for four weeks — or all at once, blasting through all four sessions in a single, “massed,” block.
Cramming may help for next-day exams. But for long-term memory, spacing out study is what works.|Sanjay Sarma, Luke Yoquinto|November 30, 2020|Washington Post
He had known that his mother, Sandy Quimby, a half-hour away in Eagle River, was a pack rat.
Smallest health providers face biggest problem finding protective gear amid coronavirus surge|Amy Goldstein|November 22, 2020|Washington Post
The researchers then removed the rats from the pen for five minutes and swapped the locations of two objects.
Warning! Junk foods can harm a teen’s brain|Sharon Oosthoek|November 19, 2020|Science News For Students
We saw that it actually reduced heroin-seeking behavior in the rat model.
How Are Psychedelics and Other Party Drugs Changing Psychiatry? (Ep. 433)|Stephen J. Dubner|October 1, 2020|Freakonomics

Before the pandemic, most people in New York City called in rats they saw in the subway, in parks or right by restaurants.
The ‘ratpocalypse’ isn’t nigh, according to service call data|Bethany Brookshire|July 14, 2020|Science News
I have no idea if he is the “friend” who ratted me out to Joseph Nye.
Damn Right I Taped Kerry’s ‘Apartheid’ Talk|Josh Rogin|May 2, 2014|DAILY BEAST
In order to save himself, one of the five arrested growers ratted out Sanderlin, whom he referred to as “Andi.”
‘Weeds’ Come to Life? Scarsdale Mom Arrested in Massive Pot Bust|Winston Ross, Eliza Shapiro|June 6, 2013|DAILY BEAST
“I ratted on the Aryan Brotherhood,” said former member Sullivan.
What’s So Scary About the Texas Aryan Brotherhood? Take a Look at the Indictments|Christine Pelisek|April 3, 2013|DAILY BEAST
People ratted him out in return for a six month suspension, Armstrong reminded Winfrey.
8 Juiciest Bits From Night Two of Lance and Oprah|Kevin Fallon|January 19, 2013|DAILY BEAST
It will be obvious that someone with a close but not affectionate relationship ratted her out.
Should You Ignore Voter Fraud?|Justin Green|November 2, 2012|DAILY BEAST
Only about that dreadful Mr Trenchard; you know the reason why he ratted?
Sybil|Benjamin Disraeli
Twenty-five years o' service in the life-savin' corps an' ain't let to go out now without these der-r-r-ratted contraptions!
The Flying Death|Samuel Hopkins Adams
If claims are ratted it is said there are strangers about, and the miners deal with rats according to their own ideas of justice.
The Black Opal|Katharine Susannah Prichard
Either the consistent Radical, or the inconsistent Conservative Party, has 'ratted' in the most barefaced manner.
Critical Studies|Ouida
He afterwards ratted and so helped to hang some of the best of them.
The Yeoman Adventurer|George W. Gough

British Dictionary definitions for rat

rat

/ (ræt) /

noun

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 worldSee also brown rat, black rat

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

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

slang, mainly US an informer; stool pigeon

informal a despicable person

smell a rat to detect something suspicious

verb rats, ratting or ratted

(intr usually foll by on) informal

to divulge secret information (about); betray the trust (of)
to default (on); abandonhe ratted on the project at the last minute

to hunt and kill rats

Derived forms of rat

ratlike, adjective

Word Origin for rat

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

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