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1

rat

play
noun \ˈrat\

Simple Definition of rat

  • : 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

Full Definition of rat

  1. 1 a :  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. 2 :  a contemptible person: as a :  one who betrays or deserts friends or associates b :  scab 3b c :  informer 2

  3. 3 :  a pad over which a woman's hair is arranged

  4. 4 :  a person who spends much time in a specified place <a mall rat>

rat·like play \-ˌlīk\ adjective

Examples of rat

  1. a dirty old building infested by rats and mice

  2. I can't believe that rat turned us in to the police!

  3. No one understands why she's with a rat like him.

  4. Every night he goes to work out with the other gym rats.



Origin of rat

Middle English, from Old English ræt; akin to Old High German ratta rat and perhaps to Latin rodere to gnaw — more at rodent


First Known Use: before 12th century


2

rat

verb

Simple Definition of rat

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

Full Definition of rat

rat·tedrat·ting

  1. intransitive verb
  2. 1 :  to betray, desert, or inform on one's associates —usually used with on

  3. 2 :  to catch or hunt rats

  4. 3 :  to work as a scab

  5. transitive verb
  6. 1 :  to give (hair) the effect of greater quantity (as by use of a rat)

  7. 2 :  to inform on :  turn in —usually used with out <ratted out his accomplice>

Examples of rat

  1. The teacher knows what we did, which means that somebody ratted.



1812

First Known Use of rat

1812


Medical Dictionary

rat

play
noun \ˈrat\

Medical Definition of rat

  1. :  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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