Source : Webster's Revised Unabridged Dictionary (1913)

Sang-froid \Sang`-froid"\, n. [F., cold blood.]
   Freedom from agitation or excitement of mind; coolness in
   trying circumstances; indifference; calmness. --Burke.

Source : WordNet®

sang-froid
     n : great coolness and composure under strain; "keep your cool"
         [syn: {aplomb}, {assuredness}, {cool}, {poise}]