confidant
noun /ˈkɒnfɪdænt/, /ˌkɒnfɪˈdɑːnt/
/ˈkɑːnfɪdænt/
(feminine confidante)
- a person that you trust and who you talk to about private or secret things
（可吐露秘密的）知己，密友 - a close/trusted confidant of the president
总统的密友／亲信 - There were times when a semi-stranger was a better confidante than a close friend.
有时候，一个半陌生的人比一个亲密的朋友更能成为知己。
词源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’. - a close/trusted confidant of the president