play it cool

1

Act cautiously and shrewdly, as in When they asked how much she earned, she played it cool. [Slang; 1940s]

2

Become or remain calm, as in When they start to tease you, just play it cool. [Slang; 1940s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.