pernicious

adjective

pər-ˈni-shəs How to pronounce pernicious (audio)
Definition of perniciousnext
as in harmful
causing or capable of causing harm the pernicious effects of illegal narcotics on society

Synonyms & Similar Words

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Antonyms & Near Antonyms

Synonym Chooser

How is the word pernicious different from other adjectives like it?

Some common synonyms of pernicious are baneful, deleterious, detrimental, and noxious. While all these words 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

When is baneful a more appropriate choice than pernicious?

The words baneful and pernicious are synonyms, but do differ in nuance. Specifically, baneful implies injury through poisoning or destroying.

the baneful notion that discipline destroys creativity

When could deleterious be used to replace pernicious?

While in some cases nearly identical to pernicious, deleterious applies to what has an often unsuspected harmful effect.

a diet found to have deleterious effects

In what contexts can detrimental take the place of pernicious?

The meanings of detrimental and pernicious largely overlap; however, detrimental implies obvious harmfulness to something specified.

the detrimental effects of excessive drinking

When is it sensible to use noxious instead of pernicious?

While the synonyms noxious and pernicious are close in meaning, noxious applies to what is both offensive and injurious to the health of a body or mind.

noxious chemical fumes

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of pernicious But herein also lie some of the issues that de-normalizing alcohol consumption brings to light, including its overlap with other, equally pernicious public health crises. — Tim Brinkhof, Time, 23 July 2026 Spector is clearly concerned with the pernicious consequences of technology, its ability to numb emotions and steer people into ideological cul-de-sacs. — Emily Nussbaum, New Yorker, 9 July 2026 That’s what the task force set out to do, and their findings, released in an official report Thursday, put meat on the bones of this pernicious problem. — The Editorial Board, Chicago Tribune, 9 July 2026 But even with federal legislation prohibiting discrimination, the pernicious virus of bias infects too many institutions. — New York Daily News Editorial Board, New York Daily News, 19 June 2026 See All Example Sentences for pernicious
Recent Examples of Synonyms for pernicious
  1. harmful
  2. dangerous
  3. detrimental
  4. damaging
  5. adverse
Adjective
  • Social media giant Meta was hit with a class action lawsuit in Australia on behalf of children and teenagers who allegedly suffered harm over the addictive design features and exposure to harmful content on its platforms Facebook and Instagram.
    — Chad de Guzman, Time, 22 Oct. 2026
  • Their contracts can run hundreds of pages, making harmful terms easy to bury.
    — Emma Witman, Fortune, 21 Oct. 2026
Definition of harmful
Adjective
  • In November 2021, crew members took shelter inside their spacecraft after a Russian anti-satellite weapons test created a dangerous cloud of debris.
    — Kurt Knutsson, FOXNews.com, 25 Oct. 2026
  • In 2015, Chicago’s public health department identified three cases of invasive meningococcal disease, a highly dangerous pathogen that can kill within hours.
    — Julie Morita, Time, 25 Oct. 2026
Definition of dangerous
Adjective
  • The company still faces numerous personal injury claims and a separate federal case involving a group of nationwide school districts that also focus on allegations that apps like Instagram have had detrimental effects on the well being of children.
    — Jonathan Vanian, CNBC, 21 Oct. 2026
  • Often, those firms’ IT heads think those changes are detrimental.
    — Scharon Harding, ArsTechnica, 21 Oct. 2026
Definition of detrimental
Adjective
  • Trump could decide that appearing powerless as Iranian attacks push up prices is more damaging than another round of military strikes.
    — Ali Vaez, Time, 21 Oct. 2026
  • Lycopene can help protect blood vessels from the damaging effects of unstable molecules known as free radicals.
    — MD Published, Verywell Health, 17 Oct. 2026
Definition of damaging
Adjective
  • In recent years, cocoa prices have surged due to adverse weather across key West African producing regions.
    — , CNBC, 23 Oct. 2026
  • Batie-Smoose seeks reinstatement or a comparable job, compensation and correction of adverse personnel records.
    — Jackson Thompson OutKick, FOXNews.com, 22 Oct. 2026
Definition of adverse

Browse Nearby Words

perms
pernicious
pernickety
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Cite this Entry

“Pernicious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/pernicious. Accessed 29 Oct. 2026.

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