rat

noun

1. Any of the numerous members of several rodent families that usually have short limbs, a pointy snout, a long, hairless tail, and a body length greater than about 12 cm, or 5 inches.
2. A medium-sized rodent belonging to the genus Rattus.

   “Similar studies of rats have employed four different intracranial resorbable, slow sustained release systems—surgical foam, a thermal gel depot, a microcapsule or biodegradable polymer beads.”

3. (informal)A person who is known for betrayal.

   “Near-synonyms: rouge, scoundrel, snake; see also Thesaurus:villain”

   “rat bastard”

   “He’s more a man than any pair of rats of you in this here house.”

   “What a rat, leaving us stranded here!”

   “"Ah, so you damn rat, this is a put-up job eh?"”

4. (informal)An informant or snitch.
5. (informal)A scab: a worker who acts against trade union policies.
6. (slang)A person who routinely spends time at a particular location.

   “Our teenager has become a mall rat.”

   “He loved hockey and was a devoted rink rat.”

7. A wad of shed hair used as part of a hairstyle.
8. A roll of material used to puff out the hair, which is turned over it.
9. (UK, slang, vulgar)Vagina, vulva.

   “Get your rat out.”

   “I don't need no dating app to tell me if I look like crap / To tell me if I'm thin or fat, to tell me should I shave my rat / I don't need no radio, no MTV, no BBC / I just need a bubble bath to set me on a higher path”

10. (abbreviation, alt-of, ellipsis, informal)Ellipsis of muskrat.

    “The price of rats began to rise and soon after the marsh froze over, spearing rats began, which was done with a one tine three-eighths inch steel rod, with a wooden handle […]”

    “Where natural marshes, or natural foods are found, are best places for raising muskrats. Louisiana and other southern states raise millions of rats, but they do not bring as good prices as northern raised ones. Delaware and Maryland have famed marshes. Other states are becoming noted for muskrat raising, also.”

11. (regional)A scratch or a score.
12. (regional)A place in the sea with rapid currents and crags where a ship is likely to be torn apart in stormy weather.
13. (slang)A ration.

    “With regards to the testing of his product, the initial blood analysis had come back confirming huge, distinctive nutritional superiority for Stewart's military ration pack. Given that the policy of the British Army is to be fully ready for war at the drop of a hat, he was sitting on the potential of supplying new rats for the entire army […]”

14. (abbreviation, alt-of, countable, initialism)Initialism of rapid antigen test.
15. (abbreviation, alt-of, countable, initialism)Initialism of Rapid Area Transit.
16. (abbreviation, alt-of, countable, initialism)Initialism of ram air turbine.
17. (abbreviation, alt-of, countable, initialism)Initialism of remote-access Trojan.
18. (abbreviation, alt-of, initialism, uncountable)Initialism of relevant alternatives theory.

verb

1. (usually)To hunt or kill rats.
2. (intransitive)To betray a political party, cause or principle; to betray someone, to desert a person or thing.
3. (informal, intransitive)To work as a scab, going against trade union policies.
4. (US)To backcomb (hair).

   “In 1962, the higher a girl's hair was ratted the more available she was, it was simply understood.”

5. (intransitive)To inform on someone; to betray someone to the police or authorities.

   “He ratted on his coworker.”

   “He is going to rat us out!”

6. (regional)To scratch or score.

   “He ratted a vertical line on his face with a pocket knife.”

7. (obsolete, rare, regional)To tear, rip, rend.

   “Ratted to shreds.”

8. Damn, drat, blast; used in oaths.

   ““But, rat me, sir,” cried Foster in bewilderment, “tis too generous—'pon honour it is. I can't consent to it. No, rat me, I can't.””

name

1. The first of the 12-year cycle of animals which appear in the Chinese zodiac related to the Chinese calendar.