Meaning
The kanji 秘 inside a circle, meaning secret or confidential in Japanese. It is the sort of stamp you might see on a classified file.
People use it for surprise plans, secret recipes, spoilers and things nobody should share: “Birthday plan for Mai ㊙️, don’t tell her” It adds a playful, mysterious tone. Pair it with 🤫 or 🤐 when you really mean keep it quiet.