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.
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
Example Sentences
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 WebThat is especially true for Michaels, who is famously imperturbable under pressure, professorially philosophical about the businesses of comedy and television, and consistently medium-cool in his overall demeanor. Bill Carter For Cnn Business Perspectives, CNN, 9 Sep. 2022 Gerald Kyd also shines as all-seeing, imperturbable Dr. Dorn, whether wearyingly suggesting Arkadina’s ailing brother simply needs to take Paracetamol or thoughtfully dispensing kindness. David Benedict, Variety, 8 July 2022 Inquisitive and imperturbable, Nelly is our guide through the story, which somehow unfolds on her initiative. Anthony Lane, The New Yorker, 21 Apr. 2022 The fat man was still sitting with the same imperturbable calm. Vladimir Sorokin, The New Yorker, 27 Sep. 2021 And the flexibility of the imperturbable Audi mill allows a fifth-gear drive from near idle to redline, a trait reminiscent of the early Lamborghini GTs and one which makes the Spyker a pussycat to drive around town. Robert Ross, Robb Report, 20 Sep. 2021 The Emmy winner stars as Del Harris, the imperturbable police chief in the languishing Rust Belt town of Buell, Pennsylvania. Ew Staff, EW.com, 10 Sep. 2021 The slow movement was infused with an imperturbable serenity, perhaps the single most elusive state to achieve in the Hollywood Bowl.Los Angeles Times, 21 Aug. 2021 And, alone among the leading founders, the great imperturbable James Madison thought the country would likely do just fine. Barton Swaim, WSJ, 2 July 2021 See More
Word History
Etymology
Middle English, from Late Latin imperturbabilis, from Latin in- + perturbare to perturb