rat

A rat is most commonly a long-tailed rodent often found near humans, sometimes as an unwelcome guest. But "rat" also has a much harsher meaning: in slang, it can mean someone who tells secrets or informs on others, especially to the authorities. Think of a sneaky character in a movie giving someone away; they might be called a rat. The context will tell you whether the word refers to an animal or to a disloyal person.

The word "rat" usually brings to mind a small rodent with a long tail, a pointed snout, and a strong ability to survive in many places. Rats live all over the world and often stay close to people, especially where food and shelter are easy to find. Because of this, they are often linked with dirt, damage, or disease, although they also have a place in nature and have been widely used in scientific research.

However, "rat" also has a strongly negative slang meaning. A rat can be someone who betrays other people by giving away secrets or informing on them. In this sense, the word is close to "snitch," "informer," or "traitor." Calling someone a rat is a serious insult because it suggests disloyalty and broken trust.

The word also appears in the verb phrase "rat on" or "rat out," which means to tell someone in authority what another person did. You might read about rats on ships or in cities, but you may also hear that someone "ratted out" a friend to the police or to a teacher. So the word can point either to a real animal or to an act of betrayal, and the situation usually makes the meaning clear.