From Longman Dictionary of Contemporary Englishlose your temper/cool/raglose your temper/cool/ragto become angrylose your temper/cool/rag with Diana was determined not to lose her temper with him. → lose
Examples from the Corpus
lose your temper/cool/rag• Bunny wasn't the only one to lose his temper.• That was plainly evident in the locker room, where Hostetler teetered on the brink of openly losing his temper.• I should not have lost my cool and behaved in that manner.• He obviously had impregnation on his mind, but by now Lydia had lost her temper and she told him to get stuffed.• I then walked across to the photographers and lost my temper, lost my head.• Never-absolutely never in my experience-did President Reagan really lose his temper or utter a rude or unkind word.• Why did he always choose to lose his temper over issues in which he was in the wrong?• She couldn't blame him for frightening Anna, for losing his temper with the child. 