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Showing results for nefarious. Search instead for nefario.
Definitions

nefarious

[ni-fair-ee-uhs] / nɪˈfɛər i əs /
ADJECTIVE
bad, sinful
Synonyms
STRONGEST
heinous horrible odious outrageous shameful vicious vile
WEAK
abominable atrocious base corrupt criminal degenerate depraved detestable dreadful evil execrable flagitious flagrant foul glaring gross infamous infernal iniquitous miscreant monstrous opprobrious perverse putrid rank rotten treacherous villainous wicked
Antonyms
STRONGEST
delightful gentle good kind magnificent nice pleasant pleasing wonderful
WEAK
honorable respectable virtuous worthy

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Related: ‘Could a nefarious caregiver steal her money?’

From MarketWatch • Mar. 19, 2026

He’s accusing them of betraying the U.S. at the behest of nefarious interests he didn’t identify, no doubt because they don’t exist.

From The Wall Street Journal • Feb. 20, 2026

But agents have to be given powerful permissions to do their jobs, and we are already seeing this being exploited in potentially nefarious ways in what are called prompt injection attacks.

From Barron's • Feb. 17, 2026

A nefarious hacker could have easily installed a virus on to my machine without me having to do anything.

From BBC • Feb. 12, 2026

Pike could not answer what White wanted to know most: Was Hale merely protecting Bryan, or was he part of a more intricate, nefarious design?

From "Killers of the Flower Moon" by David Grann

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.