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

1.
bersikap tenang, berlagak santai
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.
Ketika dia melihat mantan pacarnya, dia mencoba untuk bersikap tenang.
•
Just play it cool and don't show them you're nervous.
Cukup bersikap tenang dan jangan tunjukkan bahwa kamu gugup.