nefarious

[ni-fair-ee-uhs]

adjective

1. extremely wicked or villainous; iniquitous.

   a nefarious plot.

   Synonyms: execrable, atrocious, vile, infamous, heinous, flagitious
   Antonyms: honest, good

nefarious

/ nɪˈfɛərɪəs /

adjective

1. evil; wicked; sinful

Other Word Forms

• nefariously adverb
• nefariousness noun
• unnefarious adjective
• unnefariously adverb
• unnefariousness noun

Word History and Origins

Origin of nefarious¹

First recorded in 1595–1605; from Latin nefārius “wicked, vile,” equivalent to nefās “offense against divine or moral law” (from ne-, negative prefix + fās “law, right”) + -ius -ious

Word History and Origins

Origin of nefarious¹

C17: from Latin nefārius, from nefās unlawful deed, from nē not + fās divine law

Example Sentences

But all Mexican children are schooled in the what is taught as the nefarious U.S. legacy of invasions and land grabs.

Read more on Los Angeles Times

But these nefarious prompts can also be hiding out on the internet as AI agents built into browsers encounter online data of dubious quality or origin, and potentially booby-trapped with hidden commands from hackers.

Read more on Barron's

She added, “It doesn’t need to be something nefarious.”

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The greatest problem with this nefarious pact is that much of it sounds on the surface to be reasonable, if not desirable.

Read more on Los Angeles Times

At a time when so many relationships begin in the digital world, it can be easy to fall victim to someone with nefarious intentions.

Read more on Los Angeles Times

Related Words

• heinous 
• horrible 
• odious 
• outrageous 
• shameful 
• vicious 
• vile