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adjective per·ni·cious \pər-ˈni-shəs\

Simple Definition of pernicious

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

Source: Merriam-Webster's Learner's Dictionary

Full Definition of pernicious

  1. 1 :  highly injurious or destructive :  deadly

  2. 2 archaic :  wicked

perniciously adverb
perniciousness noun

Examples of pernicious in a sentence

  1. 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

  2. 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

  3. 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

  4. More pernicious still has been the acceptance of the author's controversial ideas by the general public.

  5. the pernicious effects of jealousy

  6. She thinks television has a pernicious influence on our children.

Origin of pernicious

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

First Known Use: 15th century

Synonym Discussion of 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>.

PERNICIOUS Defined for Kids


adjective per·ni·cious \pər-ˈni-shəs\

Definition of pernicious for Students

  1. :  causing great damage or harm <a pernicious disease> <a pernicious habit>

Medical Dictionary


adjective per·ni·cious \pər-ˈnish-əs\

Medical Definition of pernicious

  1. :  highly injurious or destructive :  tending to a fatal issue :  deadly <pernicious disease>

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