FIENDISH Synonyms: 107 Similar and Opposite Words

fiendish

adjective

ˈfēn-dish

Definition of fiendish

as in demonic

of, relating to, or worthy of an evil spirit a fiendish delight in playing cruel tricks

Synonyms & Similar Words

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Antonyms & Near Antonyms

as in brutal

having or showing the desire to inflict severe pain and suffering on others shook with fiendish laughter as he watched his victims writhe in agony

Synonyms & Similar Words

Antonyms & Near Antonyms

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of fiendish Plotting kind of my most fiendish, happy, mad scientist state. — Literary Hub, 4 May 2026 The soloist in the Sibelius was a mediocre violinist ill-equipped to deal with the concerto’s profound emotions and fiendish technical demands. — Luis Palomares, Miami Herald, 27 Feb. 2026 Jim Carrey plays the eponymous Grinch, a fiendish Whoville outlaw who declares war on the festive season. — Danny Horn, Entertainment Weekly, 29 Nov. 2025 Miller works with him to refine the routes, placing checkpoints that are both fair and fiendish. — New Atlas, 1 Nov. 2025 See All Example Sentences for fiendish

Recent Examples of Synonyms for fiendish

Adjective

There are plenty of Easter egg references to the previous films, including the reappearance of numerous demonic entities and the Red Door that serves as an entranceway to the Further’s various portals.

— Frank Scheck, HollywoodReporter, 19 Aug. 2026
Bassist Nikki Sixx arrived looking like a demonic ringmaster.

— Heidi Finley, Charlotte Observer, 18 Aug. 2026

Definition of demonic

Adjective

The Braves have Drake Baldwin and Sean Murphy atop their catching depth chart, but a brutal injury setback involving veteran backstop Sandy Leon has now forced the organization to seek out another experienced option.

— Peter Chawaga, Forbes.com, 21 Aug. 2026
Micron, as well as South Korea's SK Hynix and Samsung Electronics — the world's three major DRAM producers — had competed largely on price, contributing to the brutal boom-and-bust cycles that have long characterized the industry.

— Alexa LoMonaco, CNBC, 21 Aug. 2026

Definition of brutal

Adjective

But now Disney has shared more of what’s coming to the sinister territory just beyond the spires of the park’s Wildest Ride in the Wilderness.

— Megan duBois, Southern Living, 17 Aug. 2026
In the more familiar galaxy far, far away, their friends Hera Syndulla, Ezra Bridger, Zeb Orrelios and Chopper must face the powerful Grand Admiral Thrawn and his sinister allies, who seek to plunge the fledgling New Republic into war.

— Angeline Jane Bernabe, ABC News, 15 Aug. 2026

Definition of sinister

Adjective

Success can feel like a cruel tease, fleetingly unattainable and yet when finally achieved, too dangerous to enjoy too long.

— Dana O’Neil, CNN Money, 18 Aug. 2026
If Russia behaved badly, that was the fault of its primitive and cruel Asian side, a notion that conveniently created the fiction that Western countries are not capable of similar cruelty.

— Foreign Affairs, Foreign Affairs, 18 Aug. 2026

Definition of cruel

Adjective

Might be nice to reconnect; might also be absolutely diabolical running into each other in the crisps aisle at Waitrose.

— Lauren O’Neill, Vogue, 22 Aug. 2026
What outrages Marylanders is that this diabolical plan excludes the Preakness, devaluing it and implying the Triple Crown is irrelevant, if not dead.

— Stephen J. K. Walters, Baltimore Sun, 12 Aug. 2026

Definition of diabolical

Adjective

Detectives charged him with murder, manslaughter and criminal possession of a weapon for the vicious attack that killed his mother, 57-year-old Josefa Soto de Guzman, on Friday.

— Colin Mixson, New York Daily News, 26 Aug. 2026
Pace, skill, a vicious shot, the ability to make opposition defenders look like fools.

— James Horncastle, New York Times, 26 Aug. 2026

Definition of vicious

Adjective

Use strong security software Good security software can help protect you from malicious links, phishing attempts and other online threats that may try to steal your information.

— Kurt Knutsson, FOXNews.com, 21 Aug. 2026
Many phones silently join familiar-looking networks without user confirmation, a behavior that attackers exploit through malicious wireless access points that mimic trusted hotspots.

— Expert Panel®, Forbes.com, 20 Aug. 2026

Definition of malicious

Adjective

Cole, who has to maneuver his way around 20 savage crew members, each of whom will need to be killed, doesn’t waste a homicidal movement.

— Owen Gleiberman, Variety, 19 Aug. 2026
The savage battles of Iwo Jima and Okinawa had already demonstrated the ferocity with which Japanese forces would defend their homeland.

— James M. Scott, Time, 10 Aug. 2026

Definition of savage

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“Fiendish.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fiendish. Accessed 29 Aug. 2026.

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Synonyms of fiendish

adjective

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