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cool

1 cool /ˈkuːl/ adjective
cooler; coolest
1 cool
/ˈkuːl/
adjective
cooler; coolest
Britannica Dictionary definition of COOL
[or more cool; most cool] : somewhat cold : not warm or hot
: made of a light, thin material that helps you stay cool
[or more cool; most cool] : 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 cool; most cool] : not friendly
[or more cool; most cool] informal
: very fashionable, stylish, or appealing in a way that is generally approved of especially by young people
often used to show approval in a general way
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

— coolish

/ˈkuːlɪʃ/ adjective

— coolly

adverb

— coolness

noun [noncount]
2 cool /ˈkuːl/ verb
cools; cooled; cooling
2 cool
/ˈkuːl/
verb
cools; cooled; cooling
Britannica Dictionary definition of COOL
[+ object] : to make (someone or something) cool
often + off or down
[no object] : to become cool : to lose heat or warmth
often + off or down
[no object] : to become less strong or intense especially in emotion
often + off or down
[+ object] : to make (an emotion) less strong or intense often + off or down

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
3 cool /ˈkuːl/ noun
3 cool
/ˈkuːl/
noun
Britannica Dictionary definition of COOL

keep your cool

informal also chiefly US maintain your cool
: to remain calm

lose your cool

informal also US blow your cool
: to suddenly become very angry

the cool

: a cool time or place usually + of
4 cool /ˈkuːl/ adverb
4 cool
/ˈkuːl/
adverb
Britannica Dictionary definition of COOL
informal
: in a calm manner : in a way that does not seem unusual or excited