rat Meaning, Definition & Usage

  1. noun any of various long-tailed rodents similar to but larger than a mouse
  2. noun someone who works (or provides workers) during a strike
    strikebreaker; scab; blackleg.
  3. noun a person who is deemed to be despicable or contemptible
    git; crumb; stinker; so-and-so; scum bag; rotter; puke; dirty dog; bum; skunk; stinkpot; lowlife.
    • only a rotter would do that
    • kill the rat
    • throw the bum out
    • you cowardly little pukes!
    • the British call a contemptible person a `git'
  4. noun one who reveals confidential information in return for money
    squealer; informer; betrayer; blabber.
  5. noun a pad (usually made of hair) worn as part of a woman's coiffure
  6. verb desert one's party or group of friends, for example, for one's personal advantage
  7. verb employ scabs or strike breakers in
  8. verb take the place of work of someone on strike
    fink; scab; blackleg.
  9. verb give (hair) the appearance of being fuller by using a rat
  10. verb catch rats, especially with dogs
  11. verb give away information about somebody
    shop; give away; denounce; tell on; stag; betray; snitch; grass; shit.
    • He told on his classmate who had cheated on the exam

WordNet

Rat noun
Etymology
AS. ræt; akin to D. rat, OHG. rato, ratta, G. ratte, ratze, OLG. ratta, LG. & Dan. rotte, Sw. råtta, F. rat, Ir. & Gael radan, Armor. raz, of unknown origin. Cf. Raccoon.
Definitions
  1. (Zoöl.) One of the several species of small rodents of the genus Mus and allied genera, larger than mice, that infest houses, stores, and ships, especially the Norway, or brown, rat (M. Alexandrinus). These were introduced into Anerica from the Old World.
  2. A round and tapering mass of hair, or similar material, used by women to support the puffs and rolls of their natural hair. Local, U.S.
  3. One who deserts his party or associates; hence, in the trades, one who works for lower wages than those prescribed by a trades union. Cant ✍ "It so chanced that, not long after the accession of the house of Hanover, some of the brown, that is the German or Norway, rats, were first brought over to this country (in some timber as is said); and being much stronger than the black, or, till then, the common, rats, they in many places quite extirpated the latter. The word (both the noun and the verb to rat) was first, as we have seen, leveled at the converts to the government of George the First, but has by degrees obtained a wide meaning, and come to be applied to any sudden and mercenary change in politics." Lord Mahon.
Rat intransitive verb
Wordforms
imperfect & past participle Ratted; present participle & verbal noun Ratting
Definitions
  1. In English politics, to desert one's party from interested motives; to forsake one's associates for one's own advantage; in the trades, to work for less wages, or on other conditions, than those established by a trades union.
    Coleridge . . . incurred the reproach of having ratted, solely by his inability to follow the friends of his early days. De Quincey.
  2. To catch or kill rats. rat on (someone), to inform on an associate,to squeal.

Webster 1913