Refers to the property of being kept secret or confidential, often used in formal or technical contexts such as data protection or privacy policies.
This system has a high level of confidentiality.
We must protect the confidentiality of personal information.
機密性 also means 'confidentiality' but is more strongly associated with classified or military secrets, whereas 秘匿性 is broader and can apply to personal data or general secrecy.
Compound of 秘匿 (ひとく, 'concealment') + 性 (せい, '-ity, -ness'). The exact historical derivation is uncertain, but the word follows a common pattern for forming abstract nouns in modern Japanese.