game是游戏，做形容词可表示“勇敢的”，game face是美语中一个非正式表达，表示的是一种严肃、充满斗志，要跟别人一较高下的气场。

【例句】
He was wearing his game face in the finals。
他在决赛中斗志昂扬。

Most players had their game face on and just ignored the calls from the crowd.
大多数选手露出必胜的表情，完全无视人群中的叫喊声。