— perniciously , adv. — perniciousness , n.
/peuhr nish"euhs/ , adj.
1. causing insidious harm or ruin; ruinous; injurious; hurtful: pernicious teachings; a pernicious lie.
2. deadly; fatal: a pernicious disease.
3. Obs. evil; wicked.
[ 1515-25; perniciosus ruinous, equiv. to pernici ( es ) ruin ( per- PER- + -nici-, comb. form of nex death, murder (s. nec- ) + -ies n. suffix) + -osus -OUS ]
Syn. 1. harmful, detrimental, deleterious, destructive, damaging, baneful, noxious, malicious. 2. lethal.