Definition & Meaning of "one's lips are sealed"

What is the origin of the idiom "one's lips are sealed" and when to use it?

The idiom "one's lips are sealed" originated from the practice of physically sealing or closing one's lips to ensure silence. The phrase signifies a commitment to keeping information confidential or maintaining secrecy. It implies that the person will not disclose or reveal any sensitive or confidential information, often in response to a request or when entrusted with a secret. This idiom emphasizes a strong determination to remain silent and not divulge any information, reinforcing the idea of maintaining confidentiality or privacy.