composure
/kəm-ˈpō-zhər/
noun
a calmness or repose especially of mind, bearing, or appearance : self-possession
The witness started to break down, then paused and regained her composure.
equanimity composure sangfroid mean evenness of mind under stress. equanimity suggests a habit of mind that is only rarely disturbed under great strain. composure implies the controlling of emotional or mental agitation by an effort of will or as a matter of habit.
idiom
to remain calm : to not become upset or angry
He kept his cool even though it was clear that he was being unfairly treated.
idiom
to become angry