Dictionary.com
Thesaurus.com
Synonyms

pernicious

American  
[per-nish-uhs] / pərˈnɪʃ əs /

adjective

  1. causing insidious harm or ruin; ruinous; injurious; hurtful.

    pernicious teachings;

    a pernicious lie.

    Synonyms:
    malicious, noxious, baneful, damaging, destructive, deleterious, detrimental, harmful
  2. deadly; fatal.

    a pernicious disease.

    Synonyms:
    lethal
  3. Obsolete. evil; wicked.


pernicious British  
/ pəˈnɪʃəs /

adjective

  1. wicked or malicious

    pernicious lies

  2. causing grave harm; deadly

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • perniciously adverb
  • perniciousness noun
  • unpernicious adjective
  • unperniciously adverb

Etymology

Origin of pernicious

First recorded in 1515–25; from Latin perniciōsus “ruinous,” from pernici(ēs) “ruin” (from per- per- + -nici-, combining form of nex “death, murder” + -ēs, noun suffix) + -ōsus -ous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

High borrowing costs, he said, have had a pernicious impact on lower-income consumers without producing clear gains in inflation.

From Barron's

But if you use them as a lifestyle crutch, they can be pernicious.

From MarketWatch

Pancreatic cancer is pernicious, but five-year survival has increased three-fold since the 1990s to 13%, which the report attributes to more cancers being detected incidentally at earlier stages when they are easier to treat.

From The Wall Street Journal

The obvious dark side of this line of research is that someone who understands how to boost well-being through memory manipulation could just as easily use the same knowledge for pernicious ends.

From Los Angeles Times

Head of the National Farmers' Union Tom Bradshaw welcomed the change, telling BBC Radio 5 Live it "takes out many family farms from the eye of pernicious storm".

From BBC