rat

noun13

1. •
   an animal like a mouse but much bigger, with a long thin tail, often living near people

   • 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. — 2013
2. •
   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.
3. •
   (informal) A person who is known for betrayal.

   • What a rat, leaving us stranded here!
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. •
   (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 […] — 1910
8. •
   (slang, vulgar) Vagina, vulva.

   • Get your rat out.
9. •
   A wad of shed hair used as part of a hairstyle.
10. •
    A roll of material used to puff out the hair, which is turned over it.
11. •
    (slang) A ration.
12. •
    A scratch or a score.
13. •
    A place in the sea with rapid currents and crags where a ship is likely to be torn apart in stormy weather.

verb9

1. •
   To betray a political party, cause or principle; to betray someone, to desert a person or thing.
2. •
   To inform on someone; to betray someone to the police or authorities.

   • He ratted on his coworker.
   • He is going to rat us out!
3. •
   (informal) To work as a scab, going against trade union policies.
4. •
   To hunt or kill rats.
5. •
   (US) To backcomb (hair).

   • In 1962, the higher a girl's hair was ratted the more available she was, it was simply understood. — 2021
6. •
   To hack someone with a remote-access Trojan.
7. •
   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.” — 1904
8. •
   To scratch or score.

   • He ratted a vertical line on his face with a pocket knife.
9. •
   (no longer used, rare) To tear, rip, rend.

   • Ratted to shreds.

verb1

1. •
   To hack someone with a remote-access Trojan.

noun5

1. •
   Initialism of rapid antigen test.
2. •
   Initialism of remote-access Trojan.
3. •
   Initialism of ram air turbine.
4. •
   Initialism of Rapid Area Transit.
5. •
   Initialism of relevant alternatives theory.