Idiom
Let the cat out of the bag
If you let the cat out of the bag, you reveal a secret, usually by accident or before you were supposed to.
How people use it
It often describes a slip of the tongue: "Grandma let the cat out of the bag about the surprise party." The secret is usually harmless, like news, a gift or a plan, rather than something shameful. It is informal and common in everyday speech. You can also say "the cat is out of the bag" to mean the secret is now known and can't be hidden again. A close match is "spill the beans."
Also said: the cat is out of the bag.
Examples
- Leo let the cat out of the bag by asking Ana what she wanted for her surprise party.
- We were going to announce the new baby at dinner, but my brother let the cat out of the bag.
- Now that the cat is out of the bag, there's no point pretending the store isn't closing.
Where it comes from
The phrase appears in print in the mid-1700s, but its origin is uncertain. A common explanation links it to the older idea of buying "a pig in a poke," a pig sold in a sack: a dishonest seller might put a cat in the bag instead, and opening the bag would reveal the trick. Nobody has found evidence that this trick was common, though. Another story, about a sailor's whip kept in a bag, is also unproven.
Check yourself
1. What does it mean to let the cat out of the bag?
Answer: To reveal a secret. Letting the cat out of the bag means telling something that was meant to stay secret.
2. Which sentence uses the idiom correctly?
Answer: Sam let the cat out of the bag when he mentioned the engagement ring.. The idiom means revealing a secret, so keeping it quiet is the opposite.
Similar idioms
Word game fan? See every word hiding in CAT.