Definition of nefarious in US English:

nefarious

adjective

  • (typically of an action or activity) wicked or criminal.

    ‘the nefarious activities of the organized-crime syndicates’
    • ‘It is supported in its nefarious activities by a popular press acting as piranhas voraciously feeding on the shreds that remain.’
    • ‘It was just a rock known for nefarious activities that took place there.’
    • ‘Concerned good citizens who think they may have discovered some nefarious doings should email the anti piracy team here.’
    • ‘Through other nefarious means, the spammer has also built up a list of email addresses.’
    • ‘Al is hunting for Beta, a master criminal who makes illegal dittos of famous people for nefarious purposes.’
    • ‘They are the most nefarious villains of all because their purpose is never clear.’
    • ‘Such nefarious activity sounds absurd - we are, after all, talking about the theft of objects that exist only on screen.’
    • ‘How many people were involved in nefarious activity made the journey?’
    • ‘I don't know if this was because she was just trying to be unobtrusive, or if she thought we were up to some nefarious activity.’
    • ‘They haven't reckoned with the intervention of the French wine Mafia, who kidnap the kid for nefarious purposes.’
    • ‘If you are here on a search for nefarious things, I'm afraid I have no nefarious things.’
    • ‘Yet he is not cheating in the way most of us understand the term - he is not seeking to gain an advantage by nefarious means.’
    • ‘All this does is make celebrities out of these crooks and encourages them to continue with their nefarious activities.’
    • ‘She was also known for her escapades as a spy and for her various other nefarious activities.’
    • ‘They hit us where it hurts and do their damnedest to sell us products we neither want nor need in all manner of nefarious ways.’
    • ‘I know I sure wouldn't like to meet such dangerous and nefarious characters down a dark alleyway.’
    • ‘Also I was told that wizards keep ghosts for their nefarious activities.’
    • ‘For that, social introspection is required at all levels to identify the root causes of such nefarious crimes.’
    • ‘Criminals don't carry out their nefarious acts in and around taxis.’
    • ‘It is not a pretty wreck but its nefarious history makes it intriguing.’
    wicked, evil, iniquitous, sinful, vile, foul, monstrous, shocking, outrageous, atrocious, abominable, reprehensible, hateful, detestable, despicable, odious, contemptible, horrible, heinous, execrable, diabolical, diabolic, fiendish, vicious, murderous, barbarous, black, dark, rotten
    wicked, evil, sinful, iniquitous, villainous, criminal, heinous, atrocious, appalling, abhorrent, vile, foul, base, abominable, odious, depraved, corrupt, shameful, scandalous, monstrous, fiendish, diabolical, devilish, unholy, ungodly, infernal, satanic, dark, unspeakable, despicable, outrageous, shocking, disgraceful
    View synonyms

Origin

Early 17th century: from Latin nefarius, from nefas, nefar- ‘wrong’ (from ne- ‘not’ + fas ‘divine law’) + -ous.

Pronunciation

nefarious

/nəˈfɛriəs//nəˈferēəs/