Synonyms for Coolness (same or very similar meaning)
WordNet sense 1 (calm and unruffled self-assurance):
imperturbability, imperturbablenessWordNet sense 2 (the property of being moderately cold):
chillinessWordNet sense 3 (fearless self-possession in the face of danger):
nervelessnessWordNet sense 4 (a lack of affection or enthusiasm):
coldness, frigidity, frigidness, icinessFrom the ODE community, based on WordNetadd/edit