nefarious (adj.)

"wicked in the extreme," c. 1600, from Latin nefarius "wicked, abominable, impious," from nefas "crime, wrong, impiety," from ne- "not" (from PIE root *ne- "not") + fas "right, lawful, divinely spoken," related to fari "to speak," from PIE root *bha- (2) "to speak, tell, say." Related: Nefariously; nefariousness.