Main Entry: per·ni·cious

Pronunciation: \pər-ˈni-shəs\

Function: adjective

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

Date: 15th century

1 : highly injurious or destructive : deadly
2 archaic : wicked

— per·ni·cious·ly adverb

— per·ni·cious·ness noun

synonyms 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>.