blow one's cool. blow2(def 44).
    cool it, Slang. calm down; take it easy.
    cool one's heels. heel1(def 26).

Origin of cool

before 1000; Middle English cole, Old English cōl; cognate with Middle Low German kōl, Old High German kuoli (German kuhl). See cold, chill
Related formscool·ing·ly, adverbcool·ish, adjectivecool·ly, adverbcool·ness, nouno·ver·cool, adjectiveo·ver·cool·ly, adverbo·ver·cool·ness, nounre·cool, verbsub·cool, verb (used with object)ul·tra·cool, adjectiveun·cooled, adjectivewell-cooled, adjective

Synonyms for cool

Synonym study

1. See cold. 5. See calm.

Antonyms for cool

1, 3, 4, 7, 8. warm. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for coolest

Contemporary Examples of coolest

Historical Examples of coolest

British Dictionary definitions for coolest



moderately colda cool day
comfortably free of heata cool room
producing a pleasant feeling of coldnessa cool shirt
able to conceal emotion; calma cool head
lacking in enthusiasm, affection, cordiality, etca cool welcome
calmly audacious or impudent
informal (esp of numbers, sums of money, etc) without exaggeration; actuala cool ten thousand
(of a colour) having violet, blue, or green predominating; cold
(of jazz) characteristic of the late 1940s and early 1950s, economical and rhythmically relaxed
informal sophisticated or elegant, esp in an unruffled way
informal excellent; marvellous


not standard in a cool manner; coolly


coolnessthe cool of the evening
slang calmness; composure (esp in the phrases keep or lose one's cool)
slang unruffled elegance or sophistication


(usually foll by down or off) to make or become cooler
(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
cool it (usually imperative) slang to calm down; take it easy
cool one's heels to wait or be kept waiting
See also cool out
Derived Formscoolingly, adverbcoolingness, nouncoolish, adjectivecoolly, adverbcoolness, noun

Word Origin for cool

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

Word Origin and History for coolest



Old English col "not warm" (but usually not as severe as cold), also, of persons, "unperturbed, undemonstrative," from Proto-Germanic *koluz (cf. Middle Dutch coel, Dutch koel, Old High German kuoli, German kühl "cool," Old Norse kala "be cold"), from PIE root *gel- "cold, to freeze" (see cold (adj.)).

Applied since 1728 to large sums of money to give emphasis to amount. Meaning "calmly audacious" is from 1825. Slang use for "fashionable" is 1933, originally Black English; modern use as a general term of approval is from late 1940s, probably from bop talk and originally in reference to a style of jazz; said to have been popularized in jazz circles by tenor saxophonist Lester Young. Related: Coolly.



c.1400, "coldness, coolness," from cool (adj.). Meaning "one's self-control, composure" (the thing you either keep or lose) is from 1966.



Old English colian, "to lose warmth," also figuratively, "to lose ardor," from the root of cool (adj.). Meaning "to cause to lose warmth" is from late 14c. Related: Cooled; cooling.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with coolest


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.