adjective
cooler; coolest
[or more ~; most ~] :somewhat cold :not warm or hot
made of a light, thin material that helps you stay cool
[or more ~; most ~] :able to think and act in a calm way :not affected by strong feelings
If you are (as) cool as a cucumber, you are very calm and able to think clearly often in a difficult situation.
[or more ~; most ~] :not friendly
[or more ~; most ~] informal
very fashionable, stylish, or appealing in a way that is generally approved of especially by young people
b - used to suggest acceptance, agreement, or understanding
of a color :suggesting cool things
informal - used for emphasis in referring to a large amount of money
verb
cools; cooled; cooling
[+ obj] :to make (someone or something) cool
[no obj] :to become cool :to lose heat or warmth
[no obj] :to become less strong or intense especially in emotion
[+ obj] :to make (an emotion) less strong or intense
cool it
informal :to stop being excited, angry, noisy, etc.
cool your heels
informal :to wait for someone or something :to take a break from doing something or going someplace
noun
keep your cool
also chiefly US maintain your cool
informal :to remain calm
lose your cool
also US blow your cool
informal :to suddenly become very angry
the cool
a cool time or place - usually + of
adverb
informal :in a calm manner :in a way that does not seem unusual or excited