cool

American  

[kool] / kul /

adjective

cooler, coolest

1. moderately cold; neither warm nor cold.

   a rather cool evening.

   Antonyms:

   warm

2. feeling comfortably or moderately cold.

   I'm perfectly cool, but open the window if you feel hot.

3. imparting a sensation of moderate coldness or comfortable freedom from heat.

   a cool breeze.

   Antonyms:

   warm

4. permitting such a sensation.

   a cool dress.

   Antonyms:

   warm

5. not excited; calm; composed; under control.

   to remain cool in the face of disaster.

   Synonyms:

   quiet, placid, unruffled, self-possessed, collected

6. not hasty; deliberate.

   a cool and calculated action.

7. lacking in interest or enthusiasm.

   a cool reply to an invitation.

   Synonyms:

   lukewarm, remote, reserved, apathetic, distant

   Antonyms:

   warm

8. lacking in warmth or cordiality.

   a cool reception.

   Synonyms:

   lukewarm, remote, reserved, apathetic, distant

   Antonyms:

   warm

9. calmly audacious or impudent.

   a cool lie.

10. aloof or unresponsive; indifferent.

    He was cool to her passionate advances.

11. unaffected by emotions; disinterested; dispassionate.

    She made a cool appraisal of all the issues in the dispute.

12. Informal. (of a number or sum) without exaggeration or qualification.

    a cool million dollars.

13. (of colors) with green, blue, or violet predominating.

14. Slang.

    1. great; fine; excellent.

       a real cool comic.

    2. characterized by great facility; highly skilled or clever.

       cool maneuvers on the parallel bars.

    3. socially adept.

       It's not cool to arrive at a party too early.

    4. acceptable; satisfactory; okay.

       If you want to stay late, that's cool.

---

adverb

1. Informal. coolly.

interjection

1. Slang.

   1. (used to express acceptance).

      Okay, cool! I'll be there at 10:00.

   2. (used to express approval, admiration, etc.).

      He got the job? Cool!

noun

1. something that is cool; a cool part, place, time, etc..

   in the cool of the evening.

2. coolness.

3. calmness; composure; poise.

   an executive noted for maintaining her cool under pressure.

verb (used without object)

1. to become cool (sometimes followed by down oroff ).

   The soup cooled in five minutes. We cooled off in the mountain stream.

2. to become less ardent, cordial, etc.; become moderate.

verb (used with object)

1. to make cool; impart a sensation of coolness to.

2. to lessen the ardor or intensity of; allay; calm; moderate.

   Disappointment cooled his early zealousness.

   Synonyms:

   abate, temper

verb phrase

1. cool off to become calmer or more reasonable.

   Wait until he cools off before you talk to him again.

2. cool down. see cooldown.

3. cool out to calm or settle down; relax.

   cooling out at the beach.

idioms

1. blow one's cool. blow.

2. cool one's heels. heel.

3. cool it, calm down; take it easy.

cool British  

/ kuːl /

adjective

1. moderately cold

   a cool day

2. comfortably free of heat

   a cool room

3. producing a pleasant feeling of coldness

   a cool shirt

4. able to conceal emotion; calm

   a cool head

5. lacking in enthusiasm, affection, cordiality, etc

   a cool welcome

6. calmly audacious or impudent

7. informal (esp of numbers, sums of money, etc) without exaggeration; actual

   a cool ten thousand

8. (of a colour) having violet, blue, or green predominating; cold

9. (of jazz) characteristic of the late 1940s and early 1950s, economical and rhythmically relaxed

10. informal sophisticated or elegant, esp in an unruffled way

11. informal excellent; marvellous

---

adverb

1. not_standard in a cool manner; coolly

noun

1. coolness

   the cool of the evening

2. slang calmness; composure (esp in the phrases keep or lose one's cool )

3. slang unruffled elegance or sophistication

verb

1. to make or become cooler

2. to lessen the intensity of (anger or excitement) or (of anger or excitement) to become less intense; calm down

3. slang (usually imperative) to calm down; take it easy

4. to wait or be kept waiting

cool More Idioms  

More idioms and phrases containing cool

• keep cool
• keep one's cool
• play it cool

---

Related Words

See cold. See calm.

Other Word Forms

• coolingly adverb
• coolingness noun
• coolish adjective
• coolly adverb
• coolness noun
• overcool adjective
• overcoolly adverb
• overcoolness noun
• recool verb
• subcool verb (used with object)
• ultracool adjective
• uncooled adjective
• well-cooled adjective

Etymology

Origin of cool

First recorded before 1000; Middle English col, coul, Old English cōl; cognate with Middle Low German kōl, Old High German kuoli, German kühl; see cold, chill

Explanation

When the weather is cool, it's not quite cold but not warm either. When people are cool, they're mellow and in control. Cool has many meanings. When the weather goes from 70 degrees to 50, it cooled off. A winning pool player who starts losing also cools off. Drinking lemonade on a hot day is yet another way to cool off. When you lose your temper, you lose your cool. Hot cookies should cool before you eat them. Something fashionable is cool, but if you're cool to an idea, you're not so sure about it. Any situation that becomes less intense has cooled.

Example Sentences

Based on the main mild scenario, growth is expected to cool only slightly this year to 3.1%, from 3.4% in both its initial projection and for actual growth in 2025.

From Barron's • Apr. 17, 2026

The 31-year-old from Arizona, who is attending Coachella for the fifth time, tells me "half the fun" of car camping is "all the decorating and having a cool place to come back to".

From BBC • Apr. 17, 2026

The cease-fire announced Thursday received a cool response from Hezbollah, which has fought against an Israeli invasion of Lebanese territory.

From The Wall Street Journal • Apr. 17, 2026

Thompson called it “a cool example of how you can use A.I. to help your writing—without relying on it for any actual writing.”

From Slate • Apr. 17, 2026

She picked up a piece cool enough to eat.

From "Legendary Frybread Drive-In" by Cynthia Leitich Smith

Related Words

• abate
• calm
• calm down
• chill
• chill out
• quiet
• quiet down
• rein in
• settle down
• simmer down