Rat | Mean of rat in English Dictionary

/ˈræt/

• Noun
• a small animal that has a pointed nose and a long, thin tail
1. a dirty old building infested by rats and mice
2. a lab/laboratory rat [=a rat that is used by scientists for experiments]
3. He came in from the rain looking like a drowned rat. [=looking very wet and miserable]
• a person who is not loyal or who cannot be trusted
1. I can't believe that rat turned us in to the police!
• a person who is bad or cruel
1. No one understands why she's with a rat like him.

• a person who spends a lot of time in a specified place
1. a mall rat
2. Every night he goes to work out with the other gym rats.
• to think or suspect that something is wrong about a situation
1. She smelled a rat when her husband came home with lipstick on his collar.
• Verb
• to tell someone in authority (such as the police) about something wrong that someone has done
1. The teacher knows what we did, which means that somebody ratted.
2. I am trying to find out who ratted on me.
3. Someone ratted him out to the police.
4. They accused him of ratting out his own brother.