nefarious

adjective

ne·​far·​i·​ous ni-ˈfer-ē-əs 

: flagrantly wicked or impious : evil

nefariously adverb

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What Is the Difference Between vicious, villainous, and nefarious?

Nefarious comes from the Latin adjective nefarius and the Latin noun nefas, which means "crime." Nefas is a combination of ne- ("not") and fas, meaning "right" or "divine law."

Synonyms

• evil
• unlawful
• immoral
• sinful
• vicious
• vile
• dark
• bad
• wicked
• villainous

Choose the Right Synonym for nefarious

vicious, villainous, iniquitous, nefarious, corrupt, degenerate mean highly reprehensible or offensive in character, nature, or conduct.

vicious may directly oppose virtuous in implying moral depravity, or may connote malignancy, cruelty, or destructive violence.

a vicious gangster

villainous applies to any evil, depraved, or vile conduct or characteristic.

a villainous assault

iniquitous implies absence of all signs of justice or fairness.

an iniquitous system of taxation

nefarious suggests flagrant breaching of time-honored laws and traditions of conduct.

the nefarious rackets of organized crime

corrupt stresses a loss of moral integrity or probity causing betrayal of principle or sworn obligations.

city hall was rife with corrupt politicians

degenerate suggests having sunk to an especially vicious or enervated condition.

a degenerate regime propped up by foreign powers

Examples of nefarious in a Sentence

Moreover, those starry-eyed states inclined to perceive international relations in moral terms frequently underestimate the nefarious machinations of their competitors on the world political stage. —Richard Wolin, New Republic, 4 June 2001

… I always give the same response: Just because Frank posed for pictures with every leading capo, underboss and cement contractor of the day doesn't mean that he joined them in their nefarious underworld activities. Oh, occasionally he rode along on a hit or two, but that was just one of those social obligations … —Lewis Grossberger, Time, 21 Dec. 1998

Three-tenths of a mile uphill from our mailbox on the road, that bend is so nefarious that neophytes often skidded into a snowbank or wound up fender-deep in mud there. —Maxine Kumin, In Deep, 1987

a nefarious scheme to cheat people out of their money

the chaste heroines and nefarious villains of old-time melodramas

Recent Examples on the Web

In a 2004 study, the United States Institute of Peace said that hundreds of terrorist groups had migrated online, utilizing a tool meant for better communication for often nefarious purposes. —Richard Frankel, ABC News, 11 Sep. 2025

For example, the agency might become corrupt and those running AGI start to use the AGI for their own nefarious purposes. —Lance Eliot, Forbes.com, 10 Sep. 2025

Occasionally other nefarious actors would create their own webpages with similar domain names. —Jacob Feldman, Sportico.com, 3 Sep. 2025

This would point any nefarious civilization in the direction of the aforementioned Dyson spheres, probably. —Fran Ruiz, Space.com, 2 Sep. 2025

Word History

Etymology

Latin nefarius, from nefas crime, from ne- not + fas right, divine law; perhaps akin to Greek themis law, tithenai to place — more at do

First Known Use

1567, in the meaning defined above

Rhymes for nefarious

• aquarius
• cinereous
• gregarious
• hilarious
• malarious
• precarious
• vicarious
• carious
• scarious
• various
• multifarious

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Kids Definition

nefarious

adjective

ne·​far·​i·​ous ni-ˈfar-ē-əs 

-ˈfer-

: very wicked : evil

nefariously adverb

nefariousness noun