Webster’s Revised Unabridged Dictionary · 1913
Nefarious
Ne·fa′ri·ous, a. [L. nefarius, fr. nefas crime, wrong; ne not + fas divine law; akin to fari to speak. See No, adv., and Fate.] Wicked in the extreme; abominable; iniquitous; atrociously villainous; execrable; detestably vile.
Syn. — Iniquitous; detestable; horrible; heinious; atrocious; infamous; impious. See Iniquitous.
— Ne·fa′ri·ous·ly, adv. — Ne·fa′ri·ous·ness, n.