losing one's cool

Verb

lose one's cool (third-person singular simple present loses one's cool, present participle losing one's cool, simple past and past participle lost one's cool)

1. (idiomatic) To become upset or disconcerted; to lose one's temper.
   • But in his final singles match against Mandarino, the Menace lost his cool. Visibly rattled by noisy spectators, who chanted "Brasil! Bra-sil!" from the third set onward, he collapsed completely in the fifth set.1966 November 18, “To the Ludicrous”, in Time

   Synonyms:

   blow one's cool, blow one's top, drop one's bundle, go ape, go apeshit, hit the roof, hit the ceiling, lose it, lose one's temper, lose one's rag

   Antonyms:

   keep one's cool