To reveal a secret or surprise, typically by accident; to disclose information that was meant to be kept confidential.
This phrase likely comes from medieval markets where dishonest merchants would sell customers a pig in a bag, but substitute a less valuable cat. If the cat escaped the bag, the deception was revealed. The phrase evolved to mean any unwanted revelation of hidden truth.
The image of a cat escaping confinement perfectly captures how secrets have their own energy and want to be free! Once that metaphorical cat is out, it's impossible to get it back in - secrets, like cats, resist being controlled once they're loose.
Complete word intelligence in one call. Free tier — 50 lookups/day.