Is the phrase "smell a rat" commonly used?
Native speaker’s answer
Rebecca
"I smell a rat" is used to express that one suspects trickery or deception. It's also used to express that you believe someone is being dishonest or secretly causing harm, as "rat" is slang used to describe someone that has betrayed or cheated someone else. Ex: Our secret recipe got leaked to our competitor. I smell a rat. Ex: The engineer was suspected of being a rat by his coworkers.