Meaning: This idiom is used to describe a situation where a secret or confidential information is revealed, often unintentionally, causing surprise, embarrassment, or disruption. It implies that something previously hidden or concealed has been exposed to others.

Usage in Example Sentences:

1. “I accidentally let the cat out of the bag about Sarah’s surprise birthday party by mentioning it in front of her.”
2. “The company’s plans for expansion were supposed to be confidential, but someone let the cat out of the bag to the press.”
3. “They tried to keep their relationship a secret, but eventually, the cat was out of the bag when they were seen together at the party.”

Origin: The origin of the idiom “cat out of the bag” dates back to the 18th century in England. It is believed to have originated from the practice of dishonest merchants who would sell a pig in a bag, promising it to be a live animal, but then replacing it with a less valuable cat. If the cat was accidentally let out of the bag before the transaction was completed, the deception would be revealed. Over time, the phrase evolved to describe any situation where a secret or hidden truth is exposed.