These adjectives indicate absence of excitement or discomposure in a person, especially in times of stress. Cool usually implies merely a high degree of self-control, but it may also indicate aloofness: “Keep strong, if possible. In any case, keep cool. Have unlimited patience” (B.H. Liddell Hart). “An honest hater is often a better fellow than a cool friend” (John Stuart Blackie). Composed implies serenity arising from self-discipline: The dancer was composed as she prepared for her recital.Collected suggests self-possession: The witness remained collected throughout the questioning.Unruffled emphasizes calm despite circumstances that might elicit agitation: “with contented mind and unruffled spirit” (Anthony Trollope). Nonchalant describes a casual manner that may suggest, sometimes misleadingly, a lack of interest or concern: He reacted to the news in a nonchalant manner.Imperturbable stresses unshakable calmness usually considered as an inherent trait: “A man … /Cool, and quite English, imperturbable” (Byron). Detached implies aloofness resulting either from lack of active concern or from resistance to emotional involvement: He sat through the service with a detached air.