Found 2 items, similar to perniciously.
English → English (WordNet) Definition: perniciously perniciously adv 1: in a harmfully insidious manner; “these drugs act insidiously” [syn: insidiously] 2: in a noxiously baneful way; “this banefully poisoned climate” [syn: banefully]
English → English (gcide) Definition: Perniciously Pernicious \Per*ni"cious\, a. [L. perniciosus, from pernicies destruction, from pernecare to kill or slay outright; per + necare to kill, slay: cf. F. pernicieux. Cf. Nuisance, Necromancy.] Having the quality of injuring or killing; destructive; very mischievous; baleful; malicious; wicked. [1913 Webster] Let this pernicious hour Stand aye accursed in the calendar. --Shak. [1913 Webster] Pernicious to his health. --Prescott. [1913 Webster] Syn: Destructive; ruinous; deadly; noxious; injurious; baneful; deleterious; hurtful; mischievous. [1913 Webster] -- Per*ni"cious*ly, adv., -- Per*ni"cious*ness, n. [1913 Webster]