cool (ko?ol)adj. cool·er, cool·est 1. Neither warm nor very cold; moderately cold: fresh, cool water; a cool autumn evening.2. Giving or suggesting relief from heat: a cool breeze; a cool blouse.3. Marked by calm self-control: a cool negotiator.4. Marked by indifference, disdain, or dislike; unfriendly or unresponsive: a cool greeting; was cool to the idea of higher taxes.5. Of, relating to, or characteristic of colors, such as blue and green, that produce the impression of coolness.6. Slang a. Knowledgeable or aware of the latest trends or developments: spent all his time trying to be cool.b. Excellent; first-rate: has a cool sports car; had a cool time at the party.c. Acceptable; satisfactory: It’s cool if you don’t want to talk about it.7. Slang Entire; full: worth a cool million.adv. Informal In a casual manner; nonchalantly: play it cool.v. cooled, cool·ing, cools v.tr.1. To make less warm.2. To make less ardent, intense, or zealous: problems that soon cooled my enthusiasm for the project.3. Physics To reduce the molecular or kinetic energy of (an object).v.intr.1. To become less warm: took a dip to cool off.2. To become calmer: needed time for tempers to cool.n.1. A cool place, part, or time: the cool of early morning.2. The state or quality of being cool.3. Composure; poise: “Our release marked a victory. The nation had kept its cool” (Moorhead Kennedy).Idioms: cool it Slang 1. To calm down; relax.2. To stop doing something. cool (one’s) heels Informal To wait or be kept waiting.[Middle English cole, from Old English c?l; see gel- in Indo-European roots.]cool?ish adj.cool?ly adv.cool?ness n.Synonyms: cool, calm, composed, collected, imperturbable, nonchalant These adjectives indicate absence of excitement or discomposure in a person, especially in times of stress. Cool usually implies an alert self-possession, but it may also indicate aloofness: “Keep strong, if possible. In any case, keep cool. Have unlimited patience” (B.H. Liddell Hart).”An honest hater is often a better fellow than a cool friend” (John Stuart Blackie). Calm suggests a serenity achieved through mastery over agitation or inner turmoil: “It was like coming across a bear in the woods: you were supposed to stand still and remain calm, against every impulse” (Cheryl Strayed). Composed and collected stress self-control brought about by mental concentration: The dancer was composed as she prepared for her recital. The witness remained collected throughout the questioning. Imperturbable and unruffled suggest equanimity in the face of potentially disturbing circumstances: The crises of 1837 shook his previously imperturbable composure (James A. Henretta). Nonchalant describes a casual manner that may suggest either confidence or lack of concern: “the nonchalant way of loggers with regard to injuries” (Molly Gloss). See Also Synonyms at cold.Our Living Language The usage of cool as a general positive epithet or interjection has been part and parcel of English slang since World War II, and has even been borrowed into other languages, such as French and German. Originally this sense is a development from its use in African American Vernacular English to mean “excellent, superlative,” first recorded in written English in the early 1930s. Jazz musicians who used the term are responsible for its popularization during the 1940s. As a slang word expressing generally positive sentiment, it has stayed current (and cool) far longer than most such words. One of the main characteristics of slang is the continual renewal of its vocabulary and storehouse of expressions: in order for slang to stay slangy, it has to have a feeling of novelty. Slang expressions meaning the same thing as cool, like bully, capital, hot, groovy, hep, crazy, nervous, far-out, rad, tubular, def, and phat have for the most part not had the staying power or continued universal appeal of cool.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.cool (ku?l) adj1. 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 impudent7. informal (esp of numbers, sums of money, etc) without exaggeration; actual: a cool ten thousand. 8. (Colours) (of a colour) having violet, blue, or green predominating; cold9. (Jazz) (of jazz) characteristic of the late 1940s and early 1950s, economical and rhythmically relaxed10. informal sophisticated or elegant, esp in an unruffled way11. informal excellent; marvellousadvnot standard in a cool manner; coollyn12. coolness: the cool of the evening. 13. slang calmness; composure (esp in the phrases keep or lose one’s cool)14. slang unruffled elegance or sophisticationvb15. (usually foll by: down or off) to make or become cooler16. (usually foll by: down or off) to lessen the intensity of (anger or excitement) or (of anger or excitement) to become less intense; calm down17. cool it (usually imperative) slang to calm down; take it easy18. cool one’s heels to wait or be kept waiting[Old English c?l; related to Old Norse k?lna, Old High German kuoli; see cold, chill] ?coolish adj ?coolly adv ?coolness nCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014cool (kul) adj. 1. moderately cold; neither warm nor cold. 2. imparting a sensation of coolness: a cool breeze. 3. permitting relief from heat: a cool dress. 4. not excited; calm: remained cool in the face of disaster. 5. not hasty; deliberate: a cool and calculated action. 6. lacking in interest or enthusiasm: a cool reply to an invitation. 7. lacking in cordiality: a cool reception. 8. calmly audacious or impudent: a cool lie. 9. unresponsive; indifferent: cool to his passionate advances. 10. Informal. not exaggerated or qualified: a cool million dollars. 11. (of colors) having green, blue, or violet predominating. 12. Slang. a. great; excellent. b. highly skilled; adept: cool maneuvers on the parallel bars. c. socially adept: It’s not cool to arrive at a party too early. adv. 13. Informal. coolly: play it cool. n. 14. a cool part, place, or time: in the cool of the evening. 15. calmness; composure; poise: maintaining her cool under pressure. v.i. 16. to become cool: cooled off in the mountain stream. 17. to become less ardent or cordial. v.t. 18. to make cool; impart a sensation of coolness to. 19. to lessen the ardor or intensity of: Disappointment cooled his enthusiasm. interj. 20. Slang. (used to express approval, admiration, or the like): New car? Cool! Idioms: cool it, Slang. calm down. [before 1000; Middle English cole, Old English c?l, c. Middle Low German k?l, Old High German kuoli. See cold, chill] cool?ish, adj. cool?ly, adv. cool?ness, n. syn: See calm. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.coolPast participle: cooledGerund: coolingImperativePresentPreteritePresent ContinuousPresent PerfectPast ContinuousPast PerfectFutureFuture PerfectFuture ContinuousPresent Perfect ContinuousFuture Perfect ContinuousPast Perfect ContinuousConditionalPast ConditionalImperativecoolcoolPresentI coolyou coolhe/she/it coolswe coolyou coolthey coolPreteriteI cooledyou cooledhe/she/it cooledwe cooledyou cooledthey cooledPresent ContinuousI am coolingyou are coolinghe/she/it is coolingwe are coolingyou are coolingthey are coolingPresent PerfectI have cooledyou have cooledhe/she/it has cooledwe have cooledyou have cooledthey have cooledPast ContinuousI was coolingyou were coolinghe/she/it was coolingwe were coolingyou were coolingthey were coolingPast PerfectI had cooledyou had cooledhe/she/it had cooledwe had cooledyou had cooledthey had cooledFutureI will coolyou will coolhe/she/it will coolwe will coolyou will coolthey will coolFuture PerfectI will have cooledyou will have cooledhe/she/it will have cooledwe will have cooledyou will have cooledthey will have cooledFuture ContinuousI will be coolingyou will be coolinghe/she/it will be coolingwe will be coolingyou will be coolingthey will be coolingPresent Perfect ContinuousI have been coolingyou have been coolinghe/she/it has been coolingwe have been coolingyou have been coolingthey have been coolingFuture Perfect ContinuousI will have been coolingyou will have been coolinghe/she/it will have been coolingwe will have been coolingyou will have been coolingthey will have been coolingPast Perfect ContinuousI had been coolingyou had been coolinghe/she/it had been coolingwe had been coolingyou had been coolingthey had been coolingConditionalI would coolyou would coolhe/she/it would coolwe would coolyou would coolthey would coolPast ConditionalI would have cooledyou would have cooledhe/she/it would have cooledwe would have cooledyou would have cooledthey would have cooledCollins English Verb Tables © HarperCollins Publishers 2011cool1. To leave food to stand at room temperature until it is no longer warm to the touch.2. To refrigerate.Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited