The Meaning and Origin of the Expression: Let the Cat Out of the Bag
“Let the cat out of the bag” means… To reveal a secret unintentionally or by mistake; To disclose or divulge facts that were previously unknown.
Just like a literal cat once held in a bag, if the secret gets out, you’ll never be able to get it back into that bag again.
There is no clear history on the origin of the phrase ‘let the cat out of the bag,’ although there are two plausible theories. The first, and probably most widely accepted, is that the popular saying began at open markets in the 1300s to 1500s where people purchased livestock. According to this theory, unscrupulous sellers of piglets would quickly swap a ferrel cat for the baby pig when the buyer wasn’t paying attention. The less valuable cat would be bagged-up for easier transport and the unsuspecting buyer would not discover they had been duped until returning home and “letting the cat out of the bag.”
The tricked livestock purchaser theory has some credible evidence backing it up, as there is a similar saying about not buying a “pig in a poke” (bag) that reliably dates to the year 1555 and another similar phrase – “When a pig is offered, open the poke” – that dates to 1325. These sayings simply cautioned against buying goods that had not been properly examined and/or to ensure that no one had secretly exchanged a less valuable item for the intended purchase (similar to modern “bait and switch” scams).
The second theory for the origin of letting a cat out of the bag is associated with the early days of the British Royal Navy. This theory asserts that a whip with nine knotted cords called the ‘cat of nine tails’ or ‘cat-o’-nine-tails’ was purposely kept in a red sack that all sailors and crew were well aware of. When a sailor got out of line or did not perform his duty, the ship’s captain would have him brought in front of the entire crew and beaten with the whip, thus “letting the cat out of the bag.”
The first known print use of the phrase comes from a 1760 book review in London Magazine. The reviewer complains that – “We could have wished that the author had not let the cat out of the bag.” – which seems to imply the reviewer felt the author ruined a surprise or secret from the book.
“I was trying to keep my fishing spot a secret, but my wife went and let the cat out of the bag.”
“My sister finally let the cat out of the bag and told our parents she was pregnant.”
“Henry let the cat out of the bag about our surprise office party.”
“I wanted our 10th wedding anniversary present to my wife to be a surprise, but my daughter slipped up and let the cat out of the bag.”
Related Historical Photos:
One possible theory for the origin of letting the cat out of the bag, this illustration shows a sailor being whipped with a cat-o’-nine-tails while other sailors await their turn to flog him. (Wikipedia)