lose your cool

lose (one's) cool

To lose control of one's composure, temper, or nerve in a given situation. He really lost his cool when the waiter dropped his food. I really lost my cool during the interview.
See also: cool, lose
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

lose your cool

COMMON If you lose your cool, you suddenly get angry and behave in a bad-tempered or uncontrolled way. At this point, I lost my cool and shouted `for goodness sake, stop!' `Why don't you sit down and have a drink?' — `I don't want a drink,' Anne replied, losing her cool.
See also: cool, lose
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012

lose your cool

lose control of your temper or emotions. informal
See also: cool, lose
Farlex Partner Idioms Dictionary © Farlex 2017

keep/lose your ˈcool

(informal) stay calm/get angry, excited, etc: He was very insulting. I really don’t know how I managed to keep my cool.
See also: cool, keep, lose
Farlex Partner Idioms Dictionary © Farlex 2017
See also:
References in periodicals archive ?
When you lose your cool with one of your internal clients, with a colleague, with someone in the mailroom, or even an outside service provider, the damage to your reputation is probably worse than you realize.
You can't lose your cool during a game and there won't be a repeat.
SO THAT YON WON'T LOSE YOUR COOL OR YOUR BATTERIES THE BATTERY PACK IS A TIGHT FIT.
Don't lose your cool, because things will return to normal soon enough.
Before you lose your cool, try a couple of drops of Boots' Time To Focus aromatherapy oil on your pulse points.
BRYAN ROBSON has warned his Sheffield United players ahead of his first Steel City derby: Lose your cool and you'll lose the game.