Definition & Meaning of "open secret"in English

What is the origin of the idiom "open secret" and when to use it?

The idiom "open secret" has its origin in the concept of information or knowledge that is widely known or understood, despite not being officially acknowledged or publicly discussed. The phrase signifies that something is common knowledge or widely recognized among a particular group or community, even though it may not be openly acknowledged or admitted. The idiom is commonly used to describe situations where certain facts, rumors, or truths are widely known among people who share a common interest or connection, even though they may not be openly discussed or acknowledged.