cool

1 of 4

adjective

ˈkül 

cooler; coolest

1

: moderately cold : lacking in warmth

The plant grows best in cool climates.

2

a

: marked by steady dispassionate calmness and self-control

a cool and calculating businessperson

They stayed cool through the emergency.

It's important to keep a cool head [=remain calm] in a crisis.

b

: lacking ardor or friendliness

a cool impersonal manner

c

of jazz : marked by restrained emotion and the frequent use of counterpoint

d

: free from tensions or violence

We used to fight, but we're cool now.

3

—used as an intensive

a cool million dollars

4

: marked by deliberate effrontery or lack of due respect or discretion

a cool reply

got a cool reception

5

: facilitating or suggesting relief from heat

a cool dress

6

a

of a color : producing an impression of being cool

specifically : of a hue in the range violet through blue to green

b

of a musical tone : relatively lacking in timbre or resonance (see resonance sense 2a)

7

informal

a

: very good : excellent

That was a really cool movie.

also : all right

Is getting together Friday night cool with you?

b

: very fashionable, impressive, or appealing in a way that is generally approved of especially by young people

… not happy with the new shoes … because they were not "cool."

—Celestine Sibley

… while over 90% of children think superheroes are "cool," it was their costume and their ability to save the world they admired most …

—Nicole Goodwin

Those looking for a cool place to grab a drink with friends will want to check out this list of six special Southern California bars.

—Vanessa Franco and Anne Valdespino

coolish

ˈkü-lish 

adjective

coolly adverb

or less commonly cooly

ˈkü(l)-lē 

coolness

ˈkül-nəs 

noun

cool

2 of 4

verb

cooled; cooling; cools

intransitive verb

1

: to become cool : lose heat or warmth

placed the pie in the window to cool

—sometimes used with off or down

2

: to lose ardor or passion

His anger cooled.

transitive verb

1

: to make cool : impart a feeling of coolness to

cooled the room with a fan

—often used with off or down

A swim cooled us off a little.

2

a

: to moderate the heat, excitement, or force of : calm

cooled her growing anger

b

: to slow or lessen the growth or activity of

—usually used with off or down

wants to cool off the economy without freezing it

—Newsweek

… moved to cool down the economy.

—Sidney Rutberg

cool

3 of 4

noun

1

: a cool time, place, or situation

the cool of the evening

2

a

: absence of excitement or emotional involvement : detachment

… his ardor, her cool, his earthiness, her spirituality.

—Hubert Saal

b

: poise, composure

The player lost his cool and began yelling at the referee.

3

: hipness

cool

4 of 4

adverb

: in a casual and nonchalant manner

play it cool

Phrases

cool it

: to calm down : go easy

The word went out to the young to cool it.

—W. M. Young

cool one's heels

: to wait or be kept waiting for a long time especially from or as if from disdain or discourtesy

Word Icons

Synonyms of cool

Adjective

• stylish
• fashionable
• happening
• chic

Verb

• chill
• freeze

Noun

• detachment
• calm
• coldness
• reasonableness
• quiet

Choose the Right Synonym for cool

cool, composed, collected, unruffled, imperturbable, nonchalant mean free from agitation or excitement.

cool may imply calmness, deliberateness, or dispassionateness.

kept a cool head

composed implies freedom from agitation as a result of self-discipline or a sedate disposition.

the composed pianist gave a flawless concert

collected implies a concentration of mind that eliminates distractions especially in moments of crisis.

the nurse stayed calm and collected

unruffled suggests apparent serenity and poise in the face of setbacks or in the midst of excitement.

harried but unruffled

imperturbable implies coolness or assurance even under severe provocation.

the speaker remained imperturbable despite the heckling

nonchalant stresses an easy coolness of manner or casualness that suggests indifference or unconcern.

a nonchalant driver

Examples of cool in a Sentence

Adjective

The weather is cool today.

The surface is cool to the touch.

The plant grows best in cool climates.

I'm feeling a little cool.

We changed into some cooler clothes.

She remained calm, cool, and collected.

Verb

The fan cools the engine.

the cooling effect of the breeze

Allow the cake to cool before slicing.

the cooling of the ocean waters

I took a break from the discussion to allow my anger to cool.

His interest in her has cooled somewhat.

Noun

had a cool new hairstyle

I envy you your cool.

Adverb

Here comes Mom. Act cool and she won't suspect a thing.

Recent Examples on the Web

Adjective

Gaube’s photographs, explains Moussa, show both his interest in vernacular architecture and the penchant of Lebanese architects, designers, and builders for using thick stone and heavy wooden doors that kept interiors cool in summer and insulated in winter. —JSTOR Daily, 25 Oct. 2025

But the thought processes are cool, the way guys maneuver the game is cool. —Tyler Kepner, New York Times, 25 Oct. 2025

Verb

As the weather quickly cools, swapping your sheets can do wonders for your sleep. —Mariana Best, Better Homes & Gardens, 31 Oct. 2025

Broth was being improperly cooled in the walk-in refrigerator. —Sacbee.com, 31 Oct. 2025

Noun

Just ask Justin Bieber, who earlier this week fessed up to kind of losing his cool in the delivery room when wife Hailey Bieber was giving birth to their son, Jack Blues Bieber, last August. —Gil Kaufman, Billboard, 29 Oct. 2025

For example, orange lights mark the warm-up segment to activate body’s core, red lights are used for the toning and strength sections, while blue ones define the more relaxing cool-down and stretching bits. —Sandra Salibian, Footwear News, 28 Oct. 2025

Adverb

Check the requirements for your specific type of orchid, since some varieties are warm-growing in daytime temperatures from 80 to 90 degrees, intermediate growing from 70 to 80 degrees, or cool-growing from 60 to 70 degrees. —Karen Brewer Grossman, Southern Living, 29 Oct. 2025

To close the month, from October 25 to 31, expect sunny conditions, starting cool before warming up. —Joe Edwards, MSNBC Newsweek, 30 Sep. 2025

Word History

Etymology

Adjective

Middle English col, going back to Old English cōl, going back to West Germanic *kōlu- (whence also Middle Dutch coele "moderately cold" and, from a variant *kōlja-, Old High German kuoli), lengthened-grade derivative from the base of *kalan- "to be cold" — more at cold entry 1

Verb

Middle English colen, going back to Old English cōlian, verbal derivative from Germanic *kōl- cool entry 1 (whence also Old Saxon colon "to become cool," Old High German kuolēn)

Noun

Middle English cole, derivative of col cool entry 1

Adverb

derivative of cool entry 1

First Known Use

Adjective

before the 12th century, in the meaning defined at sense 1

Verb

before the 12th century, in the meaning defined at intransitive sense 1

Noun

15th century, in the meaning defined at sense 1

Adverb

1968, in the meaning defined above

Phrases Containing cool

• blow one's cool
• calm, cool, and collected
• cool beans
• cool/calm head
• cool customer
• cool it
• cool one's heels
• keep a cool head
• keep one's cool/composure
• keep/stay cool
• lose one's cool/composure
• maintain one's cool/composure
• play it cool
• pre-cool
• the cool

Rhymes for cool

• boule
• brule
• buhl
• drool
• fool
• ghoul
• mule
• pool
• poul
• rule
• school
• spool

Kids Definition

cool

1 of 3 adjective

ˈkül 

1

: somewhat cold : lacking in warmth

2

: not letting in or keeping in heat

cool clothes

3

: marked by steady calmness and self-control

4

: not friendly or interested

was cool toward strangers

5

: producing an impression of being cool

blue is a cool color

6

informal

a

: very good : excellent

b

: fashionable sense 1

coolish

ˈkü-lish 

adjective

coolly

ˈkül-(l)ē

adverb

coolness

ˈkül-nəs 

noun

cool

2 of 3 verb

1

: to make or become cool

2

: to make or become less excited : calm

allow tempers to cool

cool

3 of 3 noun

: a cool time or place

the cool of the night

Legal Definition

cool

intransitive verb

: to lose passion : become calm

—sometimes used with off or down

the time elapsing…is such that a reasonable man thus provoked would have cooled

—W. R. LaFave and A. W. Scott, Jr.