imperturbable

adjective

im·​per·​turb·​able ˌim-pər-ˈtər-bə-bəl 

: marked by extreme calm, impassivity, and steadiness : serene

imperturbability

ˌim-pər-ˌtər-bə-ˈbi-lə-tē 

noun

imperturbably

ˌim-pər-ˈtər-bə-blē 

adverb

Did you know?

There is an interesting time lag between the appearance of imperturbable and its antonym, perturbable. Although imperturbable is known to have existed since the middle of the 15th century, perturbable didn't show up in written English until 1800. The verb perturb (meaning "to disquiet" or "to throw into confusion") predates both imperturbable and perturbable; it has been part of English since the 14th century. All three words derive from Latin perturbare (also meaning "to throw into confusion"), which in turn comes from the combination of per- (meaning "thoroughly") and turbare, which means "to disturb." Other relatives of imperturbable include disturb and turbid.

Synonyms

• nerveless
• unflappable
• unshakable

Choose the Right Synonym for imperturbable

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 imperturbable in a Sentence

Although he seems outwardly imperturbable, he can get very angry at times.

the chef was absolutely imperturbable—even when the kitchen caught on fire

Recent Examples on the Web

Minsky is the very opposite: chipper, imperturbable, and with impeccable manners. —Jill Lepore, The New Yorker, 30 Sep. 2024

After taking office in mid-2011, Yingluck made a virtue of necessity, assuming an imperturbable and conciliatory persona in order to mollify the establishment. —Matt Wheeler, Foreign Affairs, 10 Feb. 2015

Both were introverts by nature and, for the most part, imperturbable on the court. —Cindy Shmerler, New York Times, 24 May 2024

Susie Glass, the crime boss Eddie reports to, is essentially a carbon copy of Michelle Dockery’s Rosalind, from her cherry-red lips to her sky-high stilettos to her generally imperturbable air. —Angie Han, The Hollywood Reporter, 26 Feb. 2024

Word History

Etymology

Middle English, from Late Latin imperturbabilis, from Latin in- + perturbare to perturb

First Known Use

15th century, in the meaning defined above

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Kids Definition

imperturbable

adjective

im·​per·​turb·​able ˌim-pər-ˈtər-bə-bəl 

: hard to disturb or upset

imperturbability

-ˌtər-bə-ˈbil-ət-ē 

noun

imperturbably

-ˈtər-bə-blē 

adverb