The idiom "let the cat out of the bag" means to reveal a secret, usually by accident or prematurely. It implies that information which was supposed to be kept hidden has now been made public, making it impossible to take back.
While the origin is often debated, the most popular theory traces back to 18th-century livestock markets. Dishonest sellers would reportedly put a cheap cat in a sack (a "poke") and sell it as a premium suckling pig. If the buyer opened the bag too early, the trick was exposed—the cat was let out of the bag. Another theory refers to the "cat o' nine tails" whip used for punishment in the Royal Navy, which was kept in a red leather bag; once removed, the "secret" of the upcoming punishment was out.
Register: This expression is neutral to informal. It is widely used in journalism, sports, and everyday conversation, but might be slightly too colorful for strictly formal legal or academic documents.
These examples are sourced from let the cat out of the bag on Ludwig.guru.
"Watch this… DON'T LET THE CAT OUT OF THE BAG Where does this come from?" — vice.com
"Mr. Gore simply let the cat out of the bag." — nytimes.com
"Because your own Treasury minister has let the cat out of the bag." — theguardian.com
"But I told the Traverse, who had commissioned it, and John Tiffany, the director, inadvertently let the cat out of the bag." — theguardian.com
"Redknapp replied: "Why would I let the cat out of the bag to the News of the World if I had done anything wrong?" — theguardian.com
| Phrase | Context |
|---|---|
| spill the beans | Very informal; often used when someone gives away a surprise or a juicy piece of gossip. |
| give the game away | Common in British English; implies revealing a plan or a trick that was being played. |
| blow the whistle | More formal and serious; refers to exposing illegal or unethical activity. |
| reveal the secret | Neutral and direct; suitable for any context, especially professional settings. |
| slip up | Focuses on the mistake itself rather than the specific information revealed. |
| divulge | Formal; used in legal or business contexts regarding sensitive information. |
| Expression | Idiomatic Meaning | Register | Avoid In |
|---|---|---|---|
| let the cat out of the bag | To reveal a secret accidentally or prematurely | Neutral / Informal | Formal legal contracts or literal descriptions of animals |
In modern English, this expression is almost exclusively used as a figurative idiom. If you use it to describe an actual cat escaping a bag, it will likely be interpreted as a pun or a joke. For literal situations, it is better to say the animal "escaped" or "got out."
While both mean to reveal a secret, spilling the beans is often more informal and frequently refers to gossip or a surprise party. To let the cat out of the bag often carries a stronger sense of a premature revelation that ruins a hidden plan or a deceptive trick. Both, however, emphasize the accidental nature of the disclosure.
No, because a planned announcement is intentional, whereas this idiom specifically refers to secrets revealed accidentally or prematurely. Using it for a scheduled event is a common mistake among learners. Instead, use terms like "unveiled," "announced," or "disclosed" for official, purposeful communications.
Tools