play it cool 假装冷静；故作镇定

【例句】
It's ridiculous to play it cool if someone you're mad about is mad about you too.
如果让你生气的人也在生你的气，而你还要假装冷静，那就太可笑了。

Play it cool, don't let them know how much you need the money.
要故意装作无所谓，别让他们知道你很缺钱。