Synonyms and related words :
aplomb, assurance, ataraxy, balance, calmness, composure, confidence, constraint, control, coolness, discipline, equability, equanimity, equilibrium, imperturbability, independence, level head, levelheadedness, phlegm, poise, possession, presence of mind, restraint, sangfroid, self-assurance, self-command, self-confidence, self-conquest, self-control, self-denial, self-discipline, self-government, self-mastery, self-restraint, well-regulated mind