noun
calmness, collectedness
Synonyms: accord, aplomb, assurance, balance, calm, contentment, control, cool, cool head, coolheadedness, coolness, dignity, dispassion, ease, equanimity, equilibrium, evenness, even temper, fortitude, harmony, imperturbability, inexcitability, levelheadedness, moderation, nonchalance, peace of mind, placidity, poise, polish, presence of mind, quiet, quietude, repose, sang-froid, sedateness, self-assurance, self-control, self-possession, serenity, sobriety, stability, tranquility
Antonyms: agitation, arousal, discomposure, excitement, perturbedness, upset