confidant
/ˈkɑn.fɪ.dɑnt/ noun C2- A person in whom one can confide or share one's secrets: a friend.
Plural confidants
From the library
I only refer to the matter in passing, for in my position of partner and confidant I am obliged to be particularly careful to avoid any indiscretion.
“I had only one confidant—my brother Mycroft.
There can be no question that Stapleton had a confidant, though it is unlikely that he ever placed himself in his power by sharing all his plans with him.
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