pernicious Meaning, Definition & Usage

  1. adjective satellite exceedingly harmful
    deadly; baneful; pestilent.
  2. adjective satellite working or spreading in a hidden and usually injurious way
    subtle; insidious.
    • glaucoma is an insidious disease
    • a subtle poison

WordNet

Per*ni"cious adjective
Etymology
L. pernix, -icis.
Definitions
  1. Quick; swift (to burn). R. Milton.
Per*ni"cious adjective
Etymology
L. perniciosus, from pernicies destruction, from pernecare to kill or slay outright; per + necare to kill, slay: cf. F. pernicieux. Cf. Nuisance, Necromancy.
Definitions
  1. Having the quality of injuring or killing; destructive; very mischievous; baleful; malicious; wicked.
    Let this pernicious hour Stand aye accursed in the calendar. Shak.
    Pernicious to his health. Prescott.
    Syn. -- Destructive; ruinous; deadly; noxious; injurious; baneful; deleterious; hurtful; mischievous. -- Per*ni"cious*ly, adv., -- Per*ni"cious*ness, n.

Webster 1913