lose 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.

lose one's cool

 and blow one's cool
to lose one's temper; to lose one's nerve. Wow, he really lost his cool! What a tantrum! Whatever you do, don't blow your cool.
See also: cool, lose
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • lose (one's) cool
  • lose one’s cool
  • lose one's cool
  • lose your cool
  • blow (one's) cool
  • blow cool
  • blow one’s cool
  • blow one's cool
  • blow your cool
  • cool someone out