Keep Secret
This is a face with a zipper on the mouth, and round eyes as if I will not reveal it anymore. It expresses that I will close my mouth tightly, I can keep secrets, and will not say things that I shouldn't say. When people are chatting, when the other party does not want to listen anymore, or when they hear the password is discovered, they often use this emoticon to show that they shut up, keep their mouths secret, and so on.
