- causing insidious harm or ruin; ruinous; injurious; hurtful: pernicious teachings; a pernicious lie.
- deadly; fatal: a pernicious disease.
- Obsolete. evil; wicked.
Origin of pernicious
SynonymsSee more synonyms for pernicious on Thesaurus.com
Examples from the Web for perniciously
Not long ago, polite society had only begun to tolerate slamming the Electoral College as a perniciously quaint old institution.Disunited and Without States
January 4, 2014
And probably I've behaved more foolishly and perniciously than ever you will.Fantasia of the Unconscious
D. H. Lawrence
In these matters his aims were generous, if his methods were perniciously mistaken.Shelley
He explained that Allen had been a feeble speculator, but plausible, of personal good faith, and perniciously sanguine.The Pillars of the House, Vol. II (of 2)
Charlotte M. Yonge
These indefinite expressions operated powerfully and perniciously on his imagination.Tales And Novels, Volume 5 (of 10)
But Supermanism is heresy, and it rapidly spread over the world, most perniciously influencing all intellectual life.Literature in the Making
- wicked or maliciouspernicious lies
- causing grave harm; deadly
Word Origin and History for perniciously
early 15c., from Middle French pernicios (13c., Modern French pernicieux) and directly from Latin perniciosus "destructive," from pernicies "destruction, death, ruin," from per- "completely" (see per) + necis "violent death, murder," related to necare "to kill," nocere "to hurt, injure, harm," noxa "harm, injury" (see noxious). Related: Perniciously; perniciousness.
- Tending to cause death or serious injury; deadly.