idiominformalsomeone whostayscalmand does not showtheiremotions,evenin adifficultsituation冷静的人,沉着的人,镇静的人SMART Vocabulary: related words and phrasesCalm and relaxed
(as) cool as a cucumberidiom
at (your) leisureidiom
be at peace with the worldidiom
calmly
calmness
equilibrium
free-flowing
gaily
genteel
happy-go-lucky
harmonious
peaceably
peacefully
peacefulness
phlegm
placid
placidly
sedate
without a care in the worldidiom
zen
See more results ?(Definition ofcool customerfrom theCambridge Advanced Learner's Dictionary & Thesaurus? Cambridge University Press)Examples from literature
Frank made up his mind when he saw this that the other was certainly nonchalant, or, as Frank himself expressed it, "a cool customer."
He sure is a cool customer, believe me, fellows!
You see, she must have washed the blood off her hands, and off the knife, too—a pretty cool customer she must be—and she used the sand-soap.