The San Bernardino Sun: Fighting the war on weeds in the garden pernicious, baneful, noxious, deleterious, detrimental mean exceedingly harmful. pernicious implies irreparable harm done through evil or insidious corrupting or undermining. Pernicious means harmful and subtle, such as a poison gas that causes illness in those exposed to it over the course of years.

Understanding the Context

Pernicious comes from the Latin perniciosus, "destructive," which in turn comes from pernicies, "death" or "ruin." PERNICIOUS definition: 1. having a very harmful effect or influence: 2. having a very harmful effect or influence: 3…. Learn more.

Key Insights

1. Tending to cause death or serious injury; deadly: a pernicious virus. 2. Causing great harm; destructive: pernicious rumors. Definition of pernicious adjective in Oxford Advanced Learner's Dictionary.

Final Thoughts

Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more. If you describe something as pernicious, you mean that it is very harmful. Parents are blaming not only peer pressure but also the pernicious influence of the internet. There is a pernicious culture of excellence: everything has to be not merely good but the best. Collins COBUILD Advanced Learner’s Dictionary. Copyright © HarperCollins Publishers.

Factsheet What does the adjective pernicious mean? There are three meanings listed in OED's entry for the adjective pernicious. See ‘Meaning & use’ for definitions, usage, and quotation evidence.