[ kool ]
See synonyms for: coolcoolercoolestcooling on

adjective,cool·er, cool·est.
  1. moderately cold; neither warm nor cold: a rather cool evening.

  2. feeling comfortably or moderately cold: I'm perfectly cool, but open the window if you feel hot.

  1. imparting a sensation of moderate coldness or comfortable freedom from heat: a cool breeze.

  2. permitting such a sensation: a cool dress.

  3. not excited; calm; composed; under control: to remain cool in the face of disaster.

  4. not hasty; deliberate: a cool and calculated action.

  5. lacking in interest or enthusiasm: a cool reply to an invitation.

  6. lacking in warmth or cordiality: a cool reception.

  7. calmly audacious or impudent: a cool lie.

  8. aloof or unresponsive; indifferent: He was cool to her passionate advances.

  9. unaffected by emotions; disinterested; dispassionate: She made a cool appraisal of all the issues in the dispute.

  10. Informal. (of a number or sum) without exaggeration or qualification: a cool million dollars.

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

  12. Slang.

    • great; fine; excellent: a real cool comic.

    • characterized by great facility; highly skilled or clever: cool maneuvers on the parallel bars.

    • socially adept: It's not cool to arrive at a party too early.

    • acceptable; satisfactory; okay: If you want to stay late, that's cool.

  1. Informal. coolly.

  1. Slang.

    • (used to express acceptance): Okay, cool! I'll be there at 10:00.

    • (used to express approval, admiration, etc.): He got the job? Cool!

  1. something that is cool; a cool part, place, time, etc.: in the cool of the evening.

  2. coolness.

  1. calmness; composure; poise: an executive noted for maintaining her cool under pressure.

verb (used without object)
  1. to become cool (sometimes followed by down or off): 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.

Verb Phrases
  1. cool down. See entry at cooldown.

  2. cool off, Informal. to become calmer or more reasonable: Wait until he cools off before you talk to him again.

  1. cool out, Slang. to calm or settle down; relax: cooling out at the beach.

Idioms about cool

  1. blow one's cool. blow2 (def. 48).

  2. cool it, Slang. calm down; take it easy.

  1. cool one's heels. heel1 (def. 29).

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

synonym study For cool

1. See cold. 5. See calm.

Other words for cool

Opposites for cool

Other words from cool

  • cool·ing·ly, adverb
  • cool·ish, adjective
  • cool·ly, adverb
  • cool·ness, noun
  • o·ver·cool, adjective
  • o·ver·cool·ly, adverb
  • o·ver·cool·ness, noun
  • re·cool, verb
  • sub·cool, verb (used with object)
  • ul·tra·cool, adjective
  • un·cooled, adjective
  • well-cooled, adjective

Words Nearby cool Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use cool in a sentence

British Dictionary definitions for cool


/ (kuːl) /

  1. moderately cold: a cool day

  2. comfortably free of heat: a cool room

  1. producing a pleasant feeling of coldness: a cool shirt

  2. able to conceal emotion; calm: a cool head

  3. lacking in enthusiasm, affection, cordiality, etc: a cool welcome

  4. calmly audacious or impudent

  5. informal (esp of numbers, sums of money, etc) without exaggeration; actual: a cool ten thousand

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

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

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

  9. informal excellent; marvellous

  1. not standard in a cool manner; coolly

  1. coolness: the cool of the evening

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

  1. slang unruffled elegance or sophistication

  1. (usually foll by down or off) to make or become cooler

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

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

  2. cool one's heels to wait or be kept waiting

Origin of cool

Old English cōl; related to Old Norse kōlna, Old High German kuoli; see cold, chill

Derived forms of cool

  • coolingly, adverb
  • coolingness, noun
  • coolish, adjective
  • coolly, adverb
  • coolness, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with cool


In addition to the idioms beginning with cool

  • cool as a cucumber
  • cool down
  • cool it
  • cool off
  • cool one's heels
  • cool out

also see:

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

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.