失态 (shī tài): Lose one's composure (Verb) — Meaning & Stroke Order

At such a solemn award ceremony, he actually lost his composure and shed tears out of excitement.

You suddenly got angry during the negotiation just now, wasn't that a bit of a loss of composure?

During the meeting, she lost her composure due to nervousness and stuttered while speaking.

Even when faced with provocation, he has never lost his composure in public.