cool it—(coll., imper.) stop being angry; calm down:
- “Cool it, will you Arthur!” demanded Ford. Arthur would not be deterred.
play it cool—deliberately behave in a relaxed and unemotional way:
- John dived for cover, but the cameraman played it cool, pausing to switch on the camera…
Note: The expression is not equivalent in meaning to the phrase keep one’s cool—retain one’s composure and poise:
- Mal kept his cool when Badger admitted there was a problem with the cargo.