adjective
cool
kool
adjective
1
Slightly cold; at a mildly low temperature.
"A cool breeze came off the lake in the evening."
"Store the medicine in a cool, dry place."
2
Calm and composed, especially under pressure.
"She stayed cool during the emergency and got everyone out safely."
3
(informal) Fashionable, impressive, or admirable.
"Everyone thought his new bike was really cool."
"That's a cool idea for the party."
4
(informal) Acceptable; fine.
"Is it cool if I bring a friend tonight?"
noun
1
A calm, composed manner; one's composure.
"He nearly lost his cool when the flight was cancelled."
verb
1
To become less hot, or to make something less hot.
"Let the pie cool before slicing it."
"A fan helped cool the room down."
2
To become less intense, enthusiastic, or friendly.
"Relations between the two countries have cooled in recent years."
How to Use Cool
Learner’s notesIn plain EnglishMildly cold in temperature, or (informally) calm, fashionable, or simply "okay."
Common mistake
As slang for "fine/acceptable," keep it out of formal writing — "Is that cool?" reads casual even in an email.
Common pairings
cool as a cucumber
keep your cool
lose your cool
cool down
stay cool
Word Forms
cooler comparative, cooled past tense, cools singular, coolest superlative
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A _____ breeze came off the lake in the evening.
Etymology
From Old English cōl, going back through Proto-Germanic to a root meaning "to freeze" or "be cold" — the same ancient root that gave English the word "cold."