失态 (shī tài): 礼儀を忘れること

At the company's annual dinner, he drank too much and actually shouted at his boss, completely losing his composure.

Upon hearing the terrible news, even though she was usually calm, she couldn't help but burst into tears in front of everyone, losing her composure for several minutes.

During the interview, he was so nervous that he stammered and even knocked over a glass of water, appearing very much out of composure.

At the solemn memorial service, he couldn't help but laugh out loud; this loss of composure made all the relatives and friends present very embarrassed.

As a public figure, she knows well that her every word and action is watched, so even when facing great provocation, she tries hard not to lose her composure.