confidentially
adverb
[ ˌkɒnfɪˈdɛnʃ(ə)li ]
• in a way that is intended to be private or secret; privately.
• "all queries will be treated confidentially"
Similar:
privately,
in private,
in confidence,
off the record,
quietly,
secretly,
in secret,
behind closed doors,
in camera,
sub rosa,
privily,
