rat

A small animal with a long tail that looks like a large mouse.

• A rat ran across the floor.
• We keep two rats as pets.
• Did you see the rat behind the bins?

Common phrases: pet rat, rat trap, a rat

A person who breaks your trust or helps your enemies.

• You told everyone my secret, you rat!
• She called him a rat for betraying his friends.
• Nobody trusted the rat who had sold them out.

Similar words: traitor, snake

Common phrases: a dirty rat, that rat

Someone who spends much of their time in a particular place.

• My brother is a gym rat.
• The mall rats gathered outside the food court.
• She became a library rat during her college years.

Similar words: regular

Common phrases: mall rat, gym rat

To tell the police or another authority about something wrong that someone has done.

• Please do not rat on me.
• He ratted out the gang to the police.
• Who ratted on us to the teacher?

How to use it: rat on someone (He refused to rat on his brother.); rat someone out (Someone ratted her out to the police.)

Similar words: inform on, tell on, betray

Common phrases: rat on someone, rat someone out

To cut or scratch a mark into a surface.

• He used a blade to rat the wood.
• She ratted a line into the soft surface.
• The knife had ratted a deep mark across the board.

Similar words: scratch, score

Common phrases: rat a line, rat the surface