- any of several long-tailed rodents of the family Muridae, of the genus Rattus and related genera, distinguished from the mouse by being larger.
- any of various mammals similar to or related to the long-tailed rodents of the genus Rattus.
- a scoundrel.
- Slang.
- a person who abandons or betrays their party or associates, especially in a time of trouble.
- an informer.
- a scab laborer.
- a person who frequents a specified place: a mall rat;gym rats.
- a pad with tapered ends formerly used in women's hairstyles to give the appearance of greater thickness.
- (an exclamation of disappointment, disgust, or disbelief.)
- Slang.
- to desert one's party or associates, especially in a time of trouble.
- to turn informer; squeal: He ratted on the gang, and the police arrested them.
- to work as a scab.
- to hunt or catch rats.
- to make (the hair) appear thicker by use of a small pad of material or by teasing.
- to inform on: He ratted out his partners in exchange for a lighter sentence.
- to suspect or surmise treachery; have suspicion: After noting several discrepancies in his client's story, the attorney began to smell a rat.
- 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
- a person who deserts his or her friends or associates, esp in time of trouble
- a worker who works during a strike; blackleg; scab
- an informer; stool pigeon
- a despicable person
- to detect something suspicious
- (intr usually foll by on) informal
- to divulge secret information (about); betray the trust (of)
- to default (on); abandon
- to hunt and kill rats
