- To reveal a secret, often accidentally or carelessly.
Explanation
Origin
- Uncertain origin with several theories.
- **Pig in a poke:** A common theory involves medieval markets where a scammer might try to sell a cat inside a bag (poke) pretending it was a valuable piglet. If the buyer opened the bag before paying (let the cat out of the bag), the fraud was revealed. This aligns well with revealing a hidden truth.
- **Cat-o'-nine-tails:** Another theory links it to the whip used for punishment in the British Royal Navy, which was supposedly kept in a bag. Taking it out revealed that punishment was imminent. Less directly related to revealing a general secret.
- The 'pig in a poke' theory is more widely cited for the current meaning. The expression has been used since the 18th century.
Synonyms & Related Expressions
Alternatives
Slang/Informal:
- Spilled the beans
- Blabbed / Ran their mouth
- Blew it (referring to keeping the secret)
- Let it slip
- Gave it away
Vulgar/Emphatic:
- Fucked up and told someone
- Shot their mouth off
Milder/Standard:
- Revealed the secret
- Disclosed the information
- Made it known
Situational Appropriateness
- Mostly informal to semi-formal.
- It's a common, well-understood idiom, but might sound slightly quaint or clichéd in very formal writing.
Misunderstanding Warnings
- Completely idiomatic. The literal image of a cat escaping a bag is irrelevant to the meaning. Emphasize that it means 'reveal a secret'.
Examples
- We were planning a surprise party for Sarah, but her brother let the cat out of the bag.
- Don't mention the promotion to anyone yet – I don't want to let the cat out of the bag before it's official.
- Oops, I think I just let the cat out of the bag about their engagement!
Dialogue
Alice: I bought tickets for us to see that band you love next month! Surprise!
Ben: Oh wow! That's amazing! Actually, Chloe mentioned you were planning something...
Alice: Oh, did she? Looks like she let the cat out of the bag a bit early! But I'm glad you're excited!
Social Media Examples
- Tweet: My friend accidentally let the cat out of the bag about the surprise party... oh well, guess I can stop pretending now! 😂 #surprisefail #secrets
- Facebook Post: Looks like the movie studio let the cat out of the bag with that last trailer – revealed way too much! #spoilers #movietrailer
- Reddit Comment: Did the developer just let the cat out of the bag about the release date in that interview?
Response Patterns
- Oh no! Who told?
- Really? How did that happen?
- So, it's not a secret anymore?
- Well, the cat's out of the bag now! (acknowledging the reveal)
- Expressions of surprise, disappointment, or resignation.
Common Follow-up Questions/Actions
After the cat is out of the bag:
- Who let the cat out of the bag?
- How did they find out?
- What was the person's reaction to the secret being revealed?
- Action: Dealing with the consequences (e.g., telling the person directly now, changing plans).
- Action: Mildly scolding the person who revealed the secret.
Conversation Starter
- No.
- Refers to the action of revealing a secret, usually commenting on it after it happened or warning against it.
Intonation
- Stress often on CAT and BAG. Let the CAT out of the BAG.
- Can be said with annoyance (if the secret was important), amusement (if it wasn't serious), or as a caution.
Generation Differences
- Widely understood by all generations, though perhaps used slightly more frequently by older generations (Gen X and Boomers), but still common among Millennials and Gen Z.
Regional Variations
- Common in all major English-speaking regions (US, UK, Canada, Australia, etc.).