rat

noun
\ ˈrat How to pronounce rat (audio) \

Definition of rat

 (Entry 1 of 2)

1a : any of numerous rodents (Rattus and related genera) differing from the related mice especially by considerably larger size
b : any of various similar rodents
2 : a contemptible person: such as
a : one who betrays or deserts friends or associates
3 : a pad over which a woman's hair is arranged
4 : a person who spends much time in a specified place a mall rat

rat

verb
ratted; ratting

Definition of rat (Entry 2 of 2)

intransitive verb

1 : to betray, desert, or inform on one's associates usually used with on
2 : to catch or hunt rats
3 : to work as a scab

transitive verb

1 : to give (hair) the effect of greater quantity (as by use of a rat)
2 : to inform on : turn in usually used with out ratted out his accomplice

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Other Words from rat

Noun

ratlike \ ˈrat-​ˌlīk How to pronounce rat (audio) \ adjective

Examples of rat in a Sentence

Noun a dirty old building infested by rats and mice I can't believe that rat turned us in to the police! No one understands why she's with a rat like him. Every night he goes to work out with the other gym rats. Verb The teacher knows what we did, which means that somebody ratted.
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Recent Examples on the Web: Noun Jose Irizarry called 911 to the home where his wife was staying at the time and reported that someone tried to kill him by putting rat poison in one of his cigarettes. Adam Ferrise, cleveland, "Man with mental illness disappeared hours after release from Cuyahoga County Jail, family accuses jail of switching meds," 28 Feb. 2021 But seeing the gaping inequalities, rat-race competition and distrust in government and institutions all around him, Kim bet zombies would one day slip into the South Korean psyche. Los Angeles Times, "Zombies are everywhere in South Korea, feeding on fears and anxieties," 23 Feb. 2021 But the Chicago Department of Streets and Sanitation continues rat poisoning year-round, spokeswoman Cristina Villareal said. Robert Mccoppin, chicagotribune.com, "Don’t let the wintry weather fool you, Chicago. The rats are still around. And when the temperature rises, they’ll be out in full force.," 19 Feb. 2021 Wet-nosed Magawa was formally presented with his miniature medal in a virtual ceremony from London on Friday, becoming the first rat in the PDSA's 77-year history to receive the honor. NBC News, "Rat called Magawa awarded prestigious gold medal for Cambodia landmine detection," 25 Sep. 2020 Ziebarth, a senior forward, is a rink rat in the truest sense. Jim Paulsen, Star Tribune, "Copy of Prep athletes of the week: Senior rink rat helps Cambridge-Isanti reclaim 'Rusty Skates' trophy," 2 Feb. 2021 First of all, having a talented rat take the reins of your life for a while sounds like a vacation. Halle Kiefer, Vulture, "The Rats Who Puppet Our Every Move Helped Ratatouille: The Musical Raise Over $1M for Actors Fund," 3 Jan. 2021 What this means is that your brain and my brain, and a rat's brain and a dog's brain, and maybe a lizard brain and some bird brains, all look different. Ryan Prior, CNN, "How to harness brain science for a better life, explained by a neuroscientist," 30 Dec. 2020 Released in 2007, Ratatouille tells the story of Remy (voiced by Patton Oswalt), a rat with a passion for cooking and fine cuisine. Maureen Lee Lenker, EW.com, "Ratatouille musical cooked up on TikTok will stage streaming benefit," 10 Dec. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'rat.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of rat

Noun

before the 12th century, in the meaning defined at sense 1a

Verb

1812, in the meaning defined at intransitive sense 1

History and Etymology for rat

Noun

Middle English rat, ratte, going back to Old English ræt (attested once), akin to Old Saxon ratta "rat," Middle Dutch ratte, rotte, Old High German ratta, radda, ratza (feminine weak nouns), also Old High German rato (masculine weak noun), probably going back to an ablauting paradigm *raþō (nominative), *rattaz/*ruttaz (genitive), *radeni/*rudeni (dative), going back to earlier *(H)rót-ōn, *(H)rt-n-ós, *(H)rt-én-i, of uncertain origin

Note: The origin of the etymon beyond Germanic is obscure. Regionally in German Ratz or Ratze are applied to other animals (as the dormouse and the polecat); if these senses are old, the application of the etymon to rats (Rattus rattus, Rattus norvegicus) may be secondary. Note that if the base is pre-Germanic *rat-, there is no connection to either Latin rōdere "gnaw, nibble, eat away" (see rodent) or rādere "scrape, shave" (see rase), as has often been assumed.

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Time Traveler for rat

Time Traveler

The first known use of rat was before the 12th century

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Statistics for rat

Last Updated

2 Mar 2021

Cite this Entry

“Rat.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rat. Accessed 6 Mar. 2021.

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More Definitions for rat

rat

noun

English Language Learners Definition of rat

 (Entry 1 of 2)

: a small animal that has a pointed nose and a long, thin tail
: a person who is not loyal or who cannot be trusted
: a person who is bad or cruel

rat

verb

English Language Learners Definition of rat (Entry 2 of 2)

informal : to tell someone in authority (such as the police) about something wrong that someone has done : to betray someone

rat

noun
\ ˈrat How to pronounce rat (audio) \

Kids Definition of rat

 (Entry 1 of 2)

1 : a gnawing animal with brown, black, white, or grayish fur that looks like but is larger than a mouse
2 : a person who betrays friends

rat

verb
ratted; ratting

Kids Definition of rat (Entry 2 of 2)

: to betray a friend

rat

noun
\ ˈrat How to pronounce rat (audio) \

Medical Definition of rat

: any of the numerous rodents (family Muridae) of Rattus and related genera that differ from the murid mice by their usually considerably larger size and by features of the teeth and other structures and that include forms (as the brown rat, the black rat, and the roof rat) which live in and about human habitations and in ships, have become naturalized by commerce in most parts of the world, and are destructive pests consuming or destroying vast quantities of food and other goods and acting as vectors of various diseases (as bubonic plague)

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