equanimity
/ˌē-kwə-ˈni-mə-tē/
noun
evenness of mind especially under stress
right disposition : balance
nothing could disturb his equanimity
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.