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

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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
  • Local government and outside groups have long strived to ban the popular tourist attraction that critics argue is harmful to horses’ well-being.
    — Claire Carter, The Washington Examiner, 14 Oct. 2026
  • Waters are becoming cloudier overall, while harmful algal blooms — measured through chlorophyll a levels — are trending in the wrong direction, the report found.
    — Adam Thompson, CBS News, 14 Oct. 2026
Definition of harmful
Adjective
  • Swimmers should remain out of the water due to dangerous surf conditions.
    — NC Weather Bot, Charlotte Observer, 18 Oct. 2026
  • Fresh to strong winds will produce dangerous boating conditions, high surf, life-threatening rip currents, and moderate beach erosion through at least the first half of the coming week, forecasters said.
    — Felix Rodriguez, The Orlando Sentinel, 18 Oct. 2026
Definition of dangerous
Adjective
  • Hyperscalers opine on how detrimental electrical outages are to their business.
    — Drew Robb, Time, 15 Oct. 2026
  • Kennon, who is currently being held in Falkenburg Road Jail, was released from the program due to conduct detrimental to the team, the school said.
    — Ryan Morik OutKick, FOXNews.com, 14 Oct. 2026
Definition of detrimental
Adjective
  • Strong overnight thunderstorms brought heavy rain and damaging winds to the Kansas City metro, prompting a tornado warning for Clay County and leaving thousands of people without power Wednesday morning.
    — Kansas City Star, Kansas City Star, 14 Oct. 2026
  • In a culture marked by high-power distance, that’s a particularly damaging signal.
    — Ryoji Sekido, Fortune, 13 Oct. 2026
Definition of damaging
Adjective
  • In fact, the National Trust for Historic Preservation says the nationwide average for a review is 16 days, and that 98% of those reviews conclude that the project will have no adverse effect on nearby historic resources.
    — Rachel Treisman, NPR, 15 Oct. 2026
  • High prices also a factor But despite positive weather news and whispers of an abundance of crab, other factors could affect prices in adverse ways for consumers.
    — Miami Herald, Miami Herald, 15 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 21 Oct. 2026.

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