confidant [,kɔnfi'dænt]

心腹（名词）

(noun) A highly-trusted person to whom important secrets can be told.

EXAMPLE: His company's elderly accountant was the wary executive's only confidant.

公司的老会计师是这位谨慎的高管的唯一心腹。

game face

停止工作（俚语）

The serious, intense facial expression of a professional athlete during a competition; an outward appearance that reveals nothing about one's internal feelings.

EXAMPLE: Going into the important negotiation yesterday I was very nervous, but I put on my game face so no one could tell how worried I was.

昨天在进入重要谈判时，我非常紧张，但我故作轻松，所以没人看出我有多焦虑。