to relax or calm down.

The best thing both sides can do is to cool it and then get back to talking about the problem.

Hugh stepped between the two boys and told them to cool it.

Usage notes: often used as an order:

Nikki, leave your brother alone, and, Josh, cool it!

• in the same boat
• in the same breath
• in the same league
• in the same league as
• in the same league as someone
• in the same league as something
• in the scheme of things
• in the shadow of
• in the shadow of someone
• in the shadow of something
• in the short run
• in the short term
• in the soup
• in the strictest confidence
• in the strict sense
• in the teeth of
• in the teeth of something
• in the thick of it
• in the toilet
• in the twinkling of an eye
• in the vicinity of
• in the vicinity of something
• in the wake of
• in the wake of something
• in the way