rat

any of various long-tailed rodents similar to but larger than a mouse

someone who works (or provides workers) during a strike

a person who is deemed to be despicable or contemptible; "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'"

one who reveals confidential information in return for money

a pad (usually made of hair) worn as part of a woman's coiffure

desert one's party or group of friends, for example, for one's personal advantage

employ scabs or strike breakers in

take the place of work of someone on strike

give (hair) the appearance of being fuller by using a rat

catch rats, especially with dogs

give away information about somebody; "He told on his classmate who had cheated on the exam"