per·​turb | \ pər-ˈtərb How to pronounce perturb (audio) \
perturbed; perturbing; perturbs

Definition of perturb

transitive verb

1 : to cause to be worried or upset : disquiet, unsettle Half way down the next flight, she smiled to think that a char-woman's stare should so perturb her.— Edith Wharton The crowd didn't seem to perturb them in the slightest …— Nick Hornby
2 : to throw into confusion : disorder perturbing the social order
3 : to cause to experience a perturbation — see perturbation sense 2 Newton finally realized that the planetary orbits would be only approximate ellipses, for the mutual attractions of the planets would perturb their paths.— Owen Gingerich

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Other Words from perturb

perturbable \ pər-​ˈtər-​bə-​bəl How to pronounce perturb (audio) \ adjective

Choose the Right Synonym for perturb

discompose, disquiet, disturb, perturb, agitate, upset, fluster mean to destroy capacity for collected thought or decisive action. discompose implies some degree of loss of self-control or self-confidence especially through emotional stress. discomposed by the loss of his beloved wife disquiet suggests loss of sense of security or peace of mind. the disquieting news of factories closing disturb implies interference with one's mental processes caused by worry, perplexity, or interruption. the discrepancy in accounts disturbed me perturb implies deep disturbance of mind and emotions. perturbed by her husband's strange behavior agitate suggests obvious external signs of nervous or emotional excitement. in his agitated state we could see he was unable to work upset implies the disturbance of normal or habitual functioning by disappointment, distress, or grief. the family's constant bickering upsets the youngest child fluster suggests bewildered agitation. his declaration of love completely flustered her

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With its per- prefix, perturb meant originally "thoroughly upset", though today the word has lost most of its intense edge. Perturb and perturbation are often used by scientists, usually when speaking of a change in their data indicating that something has affected some normal process. When someone is referred to as imperturbable, it means he or she manages to remain calm through the most trying experiences.

Examples of perturb in a Sentence

It perturbed him that his son was thinking about leaving school. the caller's strange remark perturbed me enough to keep me awake that night
Recent Examples on the Web Upper-level winds are weak enough so as to not perturb Pamela’s growth, but there is no upper-level high-pressure ridge to enhance Pamela’s outflow. Washington Post, 12 Oct. 2021 Richard Frye, a pediatric neurologist and autism researcher at the Phoenix Children’s Hospital in Arizona, and his colleagues have found that such factors may also perturb the health of mitochondria in people with autism. Diana Kwon, Scientific American, 18 June 2021 The more opportunities there are to perturb the parameters of a design, the more potential there is to generate valuable perspective. James Scapa, Forbes, 28 May 2021 That’s especially true for people with autoimmune diseases and syndromes that perturb the body’s autonomic nervous system, which governs everything from temperature and heartbeat to balance and digestion. Melissa Healy, Los Angeles Times, 25 Mar. 2021 Since this work showed that e-cigarettes, with or without nicotine, could perturb the microbiome, the research team thought that glycerol and glycol, common e-cigarette components, might set these devices apart from cigarettes or clean air. Jackie Rocheleau, Forbes, 4 Mar. 2021 For Gray, then, thought is a source of existential anxiety that serves only to perturb our souls. Christian Alejandro Gonzalez, National Review, 21 Feb. 2021 But if two black holes are at the core, rather than one, their orbital motions will perturb the gas around them in an orderly way, causing the light to rise and fall periodically. Clara Moskowitz, Scientific American, 22 May 2015 The construction around their downtown Denver loft was deafening, MacDonald said, and the lack of social distancing perturbed him. Los Angeles Times, oregonlive, 28 Apr. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'perturb.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of perturb

14th century, in the meaning defined at sense 1

History and Etymology for perturb

Middle English, from Middle French perturber, from Latin perturbare to throw into confusion, from per- + turbare to disturb — more at turbid

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Time Traveler for perturb

Time Traveler

The first known use of perturb was in the 14th century

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Dictionary Entries Near perturb

per tout et non per my



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Last Updated

17 Oct 2021

Cite this Entry

“Perturb.” Dictionary, Merriam-Webster, Accessed 22 Oct. 2021.

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More Definitions for perturb



English Language Learners Definition of perturb

: to cause (someone) to be worried or upset


per·​turb | \ pər-ˈtərb How to pronounce perturb (audio) \
perturbed; perturbing

Kids Definition of perturb

: to disturb in mind : trouble greatly

More from Merriam-Webster on perturb

Nglish: Translation of perturb for Spanish Speakers

Britannica English: Translation of perturb for Arabic Speakers


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