English

Definition of pernicious adjective from the Oxford Advanced Learner's Dictionary

 

pernicious

 adjective
adjective
BrE BrE//pəˈnɪʃəs//
 
; NAmE NAmE//pərˈnɪʃəs//
 
(formal)
 
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having a very harmful effect on somebody/something, especially in a way that is gradual and not easily noticed the pernicious influence of TV violence on children Ageism is equally as offensive and pernicious as sexism. Word Origin late Middle English: from Latin perniciosus ‘destructive’, from pernicies ‘ruin’, based on nex, nec- ‘death’.
See the Oxford Advanced American Dictionary entry: pernicious