play it cool
US /pleɪ ɪt kuːl/
UK /pleɪ ɪt kuːl/

1.
침착하게 행동하다, 태연한 척하다
to act in a calm, unemotional way so that people think you are not anxious or excited
:
•
When she saw her ex-boyfriend, she tried to play it cool.
전 남자친구를 봤을 때, 그녀는 침착하게 행동하려고 노력했다.
•
Just play it cool and don't show them you're nervous.
그냥 침착하게 행동하고 긴장했다는 걸 보여주지 마.