rat

[ rat ]

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.
3. Slang. a scoundrel.
4. Slang.
   1. a person who abandons or betrays their party or associates, especially in a time of trouble.
   2. an informer.
   3. a scab laborer.
5. Slang. a person who frequents a specified place: gym rats.

   a mall rat;

   gym rats.

6. 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.
   1. to desert one's party or associates, especially in a time of trouble.
   2. to turn informer; squeal:

      He ratted on the gang, and the police arrested them.

   3. 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 phrase

1. Slang. to inform on:

   He ratted out his partners in exchange for a lighter sentence.

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
3. informal.
   a worker who works during a strike; blackleg; scab
4. slang.
   an informer; stool pigeon
5. informal.
   a despicable person
6. smell a rat
   to detect something suspicious

verb

1. informal.
   intrusually foll byon
   1. to divulge secret information (about); betray the trust (of)
   2. to default (on); abandon

      he ratted on the project at the last minute

2. to hunt and kill rats

Derived Forms

• ˈratˌlike, adjective

Other Words From

• rat·like adjective

Word History and Origins

Origin of rat¹

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

Word History and Origins

Origin of rat¹

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

Idioms and Phrases

Idioms

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.

More idioms and phrases containing rat

• like a drowned rat
• smell a rat

Example Sentences

In January, stress researcher Otto Kalliokoski of the University of Copenhagen published a systematic review about the effectiveness of an experimental technique used to model depression in rats.

From Science Magazine

Scientists in Tanzania have trained rats to help detect illegal wildlife products being smuggled out of the country.

From NewsForKids.net

There he found the kitchen trousers and metal clips used to secure food lockers from rats, which he re-purposed for his escape.

From BBC

Yucca moth caterpillars, kangaroo rats and ground squirrels eat their seeds.

From Los Angeles Times

Similar sex differences have been seen in other animals, including fruit flies, rats, zebrafish and birds.

From Science Daily