ふくしん
one's confidant; trusted friend; trusted retainer
Common word
Noun, No-adjective
汚きたない手てで会社かいしゃを乗のっ取とったものの、腹心ふくしんだと思おもっていた部下ぶかに裏切うらぎられ、因果応報いんがおうほうだね。
When the trusted confidant of the person who conducted a hostile takeover of the company betrayed him, it was a sort of retributive justice.