lose one’s 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

lose one’s cool

tv. to lose control; to lose one’s temper. (Compare this with keep one’s cool.) Now, don’t lose your cool. Relax.
See also: cool, lose