- The definition of pernicious is deadly or very destructive.
An example of pernicious is the devastating effects of intense drug use.
- causing great injury, destruction, or ruin; fatal; deadly
- Rare wicked; evil
Origin: Fr pernicieux from Classical Latin perniciosus from pernicies, destruction from pernecare, to kill from per, thoroughly plush necare, to kill: see necro-
Used by arrangement with John Wiley & Sons, Inc.
- a. Tending to cause death or serious injury; deadly: a pernicious virus.b. Causing great harm; destructive: pernicious rumors.
- Archaic Evil; wicked.
Origin: Middle English, from Old French pernicios, from Latin perniciōsus, from perniciēs, destruction : per-, per- + nex, nec-, violent death; see nek-1 in Indo-European roots.
- per·niˈcious·ly adverb
- per·niˈcious·ness noun
pernicious - Medical Definition