confidential confidential /ˌkɑːnfəˈdɛnʃəl/

adjective

1. () Entrusted with private information and the confidence of another  ( confidential )
   entrusted with private information and the confidence of another
    A confidential secretary
   a confidential secretary
   
2. The level of official classification for documents next above restricted and below secret; available only to persons authorized to see documents so classified  ( confidential )
   the level of official classification for documents next above restricted and below secret; available only to persons authorized to see documents so classified
   
3. Denoting confidence or intimacy  ( confidential )
   denoting confidence or intimacy
    A confidential approach
   a confidential approach
    In confidential tone of voice
   in confidential tone of voice
   
4. (of information) given in confidence or in secret  ( confidential , secret )
   (of information) given in confidence or in secret
    This arrangement must be kept confidential
   this arrangement must be kept confidential
    Their secret communications
   their secret communications