confidant

confidant
[ˈkɒnfɪdant, ˌkɒnfɪˈdant, -dɑːnt]
(fem.阴性confidante 读音同.)
  1. a person with whom one shares a secret or private matter, trusting them not to repeat it to others
    (可向之透露秘密或个人私事的)密友,知己
语源
  1. mid 17th cent.: alteration of confident (as a noun in the same sense in the early 17th cent.), probably to represent the pronunciation of French confidente 'having full trust'
英语宝典
考试词汇表