# let the cat out of the bag

idiom · CEFR B1

Source: https://englishreference.com/idiom/let-the-cat-out-of-the-bag
Updated: 2026-08-10

## Meaning

To disclose a secret; to let a secret be known, often inadvertently.

## Examples

- He let the cat out of the bag about the party.
- We wanted it to be a surprise, but someone let the cat out of the bag.
- The firm planned to announce the merger next month, but a careless email let the cat out of the bag and shares tumbled.

## Origin

First recorded in The London Magazine (1760); traditionally linked to market fraud — selling a cat in a sack as a 'pig in a poke' — though that story is unverified. (unknown)

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.