nefarious

Infamous by way of being extremely wicked.

Wicked in the extreme; heinous; abominable; atrociously sinful or villainous; detestably vile.

Synonyms Nefarious, Execrable, Flagitious, Enormous, Villainous, Abominable, Horrible, atrocious, infamous, iniquitous, impious, dreadful, detestable. The first seven words characterize extreme wickedness. As with the words under atrocious, when loosely used they approach each other in meaning; hence only their primary meanings will be indicated here: nefarious, unspeakably wicked, impious; execrable, worthy of execration or cursing, utterly hateful; flagitious, proceeding from burning desire (as lust), grossly or brutally wicked or vile, enormous, not common in this sense except with a strong noun, as enormous wickedness, but sometimes meaning wicked beyond common measure; villainous, worthy of a villain, greatly criminal or capable of great crimes; abominable, loathsome in wickedness, the object of a religious detestation; horrible, exciting horror, mental agitation, or shrinking; shocking: it is less common as applied to moral conduct, See abandoned, atrocious, criminal, and irreligious.