pernicious

adjective
per·​ni·​cious | \pər-ˈni-shəs \

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

There’s no telling exactly how far the Court will push this logic, but the pernicious thing about it is that the initial premise in the campaign finance cases that there is an intimate connection between money and speech is not totally absurd. Matthew Yglesias, Vox, "Brett Kavanaugh and the new judicial activism," 12 July 2018 Revelations about pernicious advertising by Russian operatives, chicanery by Cambridge Analytica, and questionable sharing of user data have left many Americans skeptical about Facebook . Daniel Gallant, WSJ, "How to Beat the Zuckerberg Casino," 8 July 2018 Artificial intelligence offers an abundance of new ways to research and treat this pernicious disease. Robert Channick, chicagotribune.com, "$25 million gift will help Northwestern Medicine develop artificial intelligence to treat heart disease," 26 June 2018 Most pernicious: American women are less likely to run for office than women in other countries. Amanda Erickson, Washington Post, "Spain’s new cabinet is majority female. Here’s how unusual that is.," 7 June 2018 But for the past 15 years or so, there’s been an even more pernicious obstacle facing teachers: students constantly distracted by their cellphones. BostonGlobe.com, "Students check their devices at the cellphone hotel," 1 June 2018 But the most pernicious Myth, number Three, posits that Palestinians are sole authors of their economic misery. Trudy Rubin, Philly.com, "Truth about Gaza: 3 myths keeping U.S., Jerusalem from owning up to their roles in the crisis | Trudy Rubin," 18 May 2018 Not everyone among us has an unlimited choice of gadgets to pick from, but those who do should insist on having the cleanest, lightest experience, stripped of the most pernicious forms of bloatware. Vlad Savov, The Verge, "Isn’t it time we declared our independence from bloatware?," 4 July 2018 Perhaps the most unfair and pernicious misuse of relying on standardized test scores as gatekeepers to professions such as medicine and law is to the 20% of the population who are dyslexic. WSJ, "The Uses and Misuses of the ‘Gatekeeper’ SAT," 30 Mar. 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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Last Updated

1 Oct 2018

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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

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

pernicious

adjective
per·​ni·​cious | \pər-ˈni-shəs \

Kids Definition of pernicious

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

pernicious

adjective
per·​ni·​cious | \pər-ˈnish-əs \

Medical Definition of pernicious 

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

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