Let the cat out of the bag is a common saying that means to make a secret known.
The Origin Of ‘Let The Cat Out Of The Bag’
The origin of the phrase let the cat out of the bag is not certain. However, there are theories about where it may have come from:
- One theory has to do with merchants who were looking to make some coin by selling piglets. When a customer bought a young pig from them, the merchant would put it into a bag and give it to them. However, the more dishonest merchants had other plans in mind. While out of the customer’s view, these dishonest merchants would swap out the piglet with a cat. Why? Maybe pigs were more valuable, so by switching them, it saved money. Regardless, the customer, being none the wiser, would take the bag and go home. There, they would let the cat out of the bag and the merchant’s trick would be discovered.
Now, there are a few problems with this theory. For one, what if the customer immediately looked in the bag after the transaction? I guess the bag could have been tied at the top to prevent that, but even so, the customer would eventually find the cat in their bag. Then wouldn’t they simply return to the merchant and complain? The merchant would ruin their reputation and business in no time!
2. The second theory has to do with a multi-tailed whip that was called a “cat o’ nine tails,” the shortened form being “the cat.” This whip was used for the physical punishment of sailors who broke certain rules (such as theft, I think). This whip, or “cat” was kept in a bag, perhaps to keep the leather from drying out. Anyway, if a time came for a sailor to receive punishment, “the cat” was taken out of the bag, hence the phrase.
So those are two theories I’ve heard about this phrase’s origin. Keep in mind that they are merely theories and it’s possible the expression did not originate from either.
What about its earliest known appearance in print? The earliest I could find it used as an idiom is from The London Magazine, January 1760:
“We could have wished that the strange genious, author of this piece, had not let the cat out of the bag; for it is such a mad, ranting, swearing, caterwauling pus*, that we fear no sober family will be troubled with her.”
This means that the phrase is at least over 250 years old.
“This surprise party we’re throwing for Jessica is going to be great!”
”Oh, was this supposed to be a surprise? I might have let the cat out of the bag when I spoke to her earlier today.”