adverb
US/ˌkɑːn.fɪˈden.ʃəl.i/
UK/ˌkɒn.fɪˈden.ʃəl.i/
in a way that is meant to be kept secret between you and one other person
In context
She told me confidentially that she was planning to leave the company next month.
Short entry. Full notes coming.