adj.
Pronunciation: p ə r- ' ni-sh ə s
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>.