‘私密’ (sī mì) is an adjective meaning ‘confidential’ or ‘intimate’, describing information, spaces, or relationships that are intended to be kept private and not shared publicly. The first character 私 (sī) means ‘private’ or ‘personal’, while 密 (mì) means ‘secret’, ‘close’, or ‘dense’—together they emphasize a high degree of privacy and discretion. It’s commonly used in formal and semi-formal contexts, such as healthcare, digital security, counseling, and personal relationships.

This word carries a neutral-to-positive connotation: it suggests respect for boundaries rather than secrecy with negative intent. Unlike the more clinical term 机密 (jī mì, ‘classified’), 私密 implies personal sensitivity rather than institutional secrecy. It often modifies nouns like 信息 (information), 空间 (space), 关系 (relationship), or 对话 (conversation), and can also function predicatively (e.g., 这个话题很私密).