The definition of pernicious is deadly or very destructive.
(adjective)An example of pernicious is the devastating effects of intense drug use.
See pernicious in Webster's New World College Dictionary
adjective
Origin: Fr pernicieux < L perniciosus < pernicies, destruction < pernecare, to kill < per, thoroughly + necare, to kill: see necro-
Related Forms:
See pernicious in American Heritage Dictionary 4
adjective
Origin:
Origin: Middle English
Origin: , from Old French pernicios
Origin: , from Latin perniciōsus
Origin: , from perniciēs, destruction
Origin: : per-, per-
Origin: + nex, nec-, violent death; see nek-1 in Indo-European roots
.Related Forms:
Learn more about pernicious