pernicious

adjective
per·​ni·​cious | \ pər-ˈni-shəs How to pronounce pernicious (audio) \

Definition of pernicious

1 : highly injurious or destructive : deadly
2 archaic : wicked

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Other Words from pernicious

perniciously adverb
perniciousness noun

Choose the Right Synonym for pernicious

pernicious, baneful, noxious, deleterious, detrimental mean exceedingly harmful. pernicious implies irreparable harm done through evil or insidious corrupting or undermining. the claim that pornography has a pernicious effect on society baneful implies injury through poisoning or destroying. the baneful notion that discipline destroys creativity noxious applies to what is both offensive and injurious to the health of a body or mind. noxious chemical fumes deleterious applies to what has an often unsuspected harmful effect. a diet found to have deleterious effects detrimental implies obvious harmfulness to something specified. the detrimental effects of excessive drinking

insidious, sinister, or pernicious?

Few would choose to be associated with people or things that are insidious, sinister, or pernicious; all three of these words have decidedly unpleasant meanings, each with its own particular shade of nastiness.

Insidious comes from a Latin word for “ambush” (insidiae), which is fitting, as this word often carries the meanings “deceitful,” “stealthy,” or “harmful in an imperceptible fashion.” The first two meanings may be applied to people or things (“an insidious enemy,” “an insidious plot”), while the last is usually applied to things (“insidious problems,” “insidious sexism”), in particular to the gradual progress of a disease (“an insidious malignancy”).

Sinister comes from a Latin word meaning “on the left side, unlucky, inauspicious.” Although it is commonly used today in the sense “evil” (“a sinister cult leader”; “a sinister plot”), it may also suggest an ominous foreshadowing of some unfavorable turn of events (“a sinister omen”).

Pernicious has largely stayed true to its etymological root, the Latin noun pernicies “ruin, destruction.” Its original meaning in English, “highly injurious or destructive,” usually applies to things (“pernicious apathy,” “pernicious effects”) and medical conditions (“pernicious fever,” pernicious anemia). When applied to people, pernicious means “wicked.”

Examples of pernicious in a Sentence

The notion that poll data are a legitimate form of news has to be one of the most pernicious tenets of late-twentieth-century American journalism … — Barbara Ehrenreich, Nation, 20 Nov. 1995 The more it [the Papacy] took part in the temporal conflicts with consistently pernicious result, the more impotent among the monarchs it revealed itself … — Barbara W. Tuchman, The March of Folly, 1984 At its most pernicious, paper entrepreneurialism involves little more than imposing losses on others for the sake of short-term profits for the firm. — Robert B. Reich, Atlantic, March 1983 More pernicious still has been the acceptance of the author's controversial ideas by the general public. the pernicious effects of jealousy She thinks television has a pernicious influence on our children.
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Recent Examples on the Web

Attackers, who infected the city's systems with the pernicious SamSam malware, asked for a ransom of roughly $50,000 worth of bitcoin. Lily Hay Newman, WIRED, "Atlanta Spent $2.6M to Recover From $52,000 Ransomware Scare," 23 Apr. 2018 Identity politics is perhaps the most pernicious and backward policy of the 21st century. WSJ, "How Identity Politics Admissions Hurts Most College Students," 14 Feb. 2019 But The Little Stranger opts to home in on whether its other characters’ experiences of Faraday’s pernicious influence are all in their heads. Aja Romano, Vox, "How The Little Stranger uses its ghost story to mask a study in toxic masculinity," 6 Sep. 2018 Owens for being a pernicious influence in the locker room. Jason Gay, WSJ, "Football’s Ready to Roll. Is America?," 26 July 2018 One part of the UNC administrative brain dimly perceives the pernicious effect of preferences on academic success. Heather Mac Donald, WSJ, "Diversity Delusions at North Carolina," 10 Feb. 2019 But the show has been especially pernicious for the queen herself. Dan Barna, Glamour, "Queen Elizabeth Reportedly Wasn't Happy With This Scene in Season 2 of The Crown," 25 Sep. 2018 That information bolstered economists who believe that recent signs of slowing growth reflect temporary factors, like an especially pernicious flu season that kept many workers home and hurt business. Jack Ewing, New York Times, "With Eurozone Economy Wavering, E.C.B. Leaves Policy Unchanged," 25 Apr. 2018 Something invisible and pernicious seems to be preventing even good literary men from either reaching for books with women’s names on the spines, or from summoning women’s books to mind when asked to list their influences. New York Times, "Lauren Groff: By the Book," 24 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pernicious.' 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 pernicious

15th century, in the meaning defined at sense 1

History and Etymology for pernicious

Middle English, from Anglo-French, from Latin perniciosus, from pernicies destruction, from per- + nec-, nex violent death — more at noxious

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Statistics for pernicious

Last Updated

14 May 2019

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Time Traveler for pernicious

The first known use of pernicious was in the 15th century

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More Definitions for pernicious

pernicious

adjective

English Language Learners Definition of pernicious

formal : causing great harm or damage often in a way that is not easily seen or noticed

pernicious

adjective
per·​ni·​cious | \ pər-ˈni-shəs How to pronounce pernicious (audio) \

Kids Definition of pernicious

: causing great damage or harm a pernicious disease a pernicious habit

pernicious

adjective
per·​ni·​cious | \ pər-ˈnish-əs How to pronounce pernicious (audio) \

Medical Definition of pernicious

: highly injurious or destructive : tending to a fatal issue : deadly pernicious disease

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Comments on pernicious

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