sang-froid(n = noun.attribute) aplomb, assuredness, cool, poise - great coolness and composure under strain; "keep your cool"
is a kind of calm, calmness, composure, equanimity
Freedom from agitation or excitement of mind; coolness in trying circumstances; indifference; calmness. Burke. [1913 Webster]
sang-froid, n. composure, coolness, etc., in danger or under agitating circumstances.
Etymology:
F, = cold blood