Nefarious

Part of speech: adjective (a.)

Wicked in the extreme; abominable; iniquitous; atrociously villainous; execrable; detestably vile.

Synonyms: Iniquitous; detestable; horrible; heinious; atrocious; infamous; impious. See Iniquitous. Ne*fa"ri*ous*ly, adv. Ne*fa"ri*ous*ness, n.