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 Across the short films, Early plays, among other roles, a smiling, fiendish mall pop act; the shy, offbeat child of an overbearing stage mom; and an extra in a makeup chair whose instruments, his face and his voice, are progressively hampered by prosthetics. — Lauren Michele Jackson, New Yorker, 7 June 2026 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 See All Example Sentences for fiendish

Recent Examples of Synonyms for fiendish

Adjective

Short enough to read in a single sitting, Sara Gran’s chilling story of an architect succumbing to demonic possession will leave readers stunned and unsettled.

— David Faris, TheWeek, 23 Oct. 2026
In 1999, demonic rollerblading triplets armed with hockey sticks laid cross-checks on the likes of Bud Cort and Chris Rock in Kevin Smith’s Dogma.

— Brian Davids, HollywoodReporter, 21 Oct. 2026

Definition of demonic

Adjective

Now in his 25th year on television, Chuck has built a beloved media career through brutal honesty.

— Alejandro Avila OutKick, FOXNews.com, 23 Oct. 2026
Although the decrease in shot volume wasn’t quite as dramatic, Giddey went 1-for-10 from the field and scored only two points in Wednesday’s brutal beatdown by the Raptors.

— Julia Poe, Chicago Tribune, 22 Oct. 2026

Definition of brutal

Adjective

Feathers McGraw, the sinister penguin villain from the Wallace & Gromit films, also makes a Hitchcockian cameo.

— Scott Roxborough, HollywoodReporter, 22 Oct. 2026
Other examples are more sinister—for instance, the far-right takeover of Croatian Wikipedia, or efforts by corporations to launder their images.

— Julian Lucas, New Yorker, 21 Oct. 2026

Definition of sinister

Adjective

Participants fell into their roles a little too well and, after a prisoner rebellion, increasingly cruel forms of punishment from the guards and a number of students suffering mental breakdowns, the experiment was ended on the sixth day.

— Marlow Stern, Variety, 25 Oct. 2026
But these townswomen — whether the undersexed Bakerwoman (Ella Bruccoleri ) or the prim, cruel busybody the Tailor’s Wife (a deliciously scheming Elizabeth Debicki) — are deeply unhappy with their own lot in life.

— Angelica Jade Bastién, Vulture, 22 Oct. 2026

Definition of cruel

Adjective

Numerous treatise writers began to insist that anyone who doubts the diabolical empowerment of women-as-witches is self-deluded and dangerous.

— Literary Hub, Literary Hub, 14 Oct. 2026
Almost as soon as Jackie enters her flat there, she is accosted by gunmen, narrowly escaping before learning the diabolical and psychopathic mercenaries, The Seven Demons, have been tasked with ending her life.

— Aramide Tinubu, Variety, 2 Oct. 2026

Definition of diabolical

Adjective

The vicious cycle of the current model, of course, is that to become marketable a team needs to get and retain good players, and to do that a school has to spend money, which cycles the whole thing back to the start.

— Dana O’Neil, CNN Money, 24 Oct. 2026
Governments were expected to rescue struggling banks, which held large amounts of sovereign debt, creating a vicious cycle.

— Jenni Reid,Chloe Taylor, CNBC, 23 Oct. 2026

Definition of vicious

Adjective

The malicious system component silently installs apps that look like weather tools, app lockers and other everyday utilities.

— Kurt Knutsson, FOXNews.com, 23 Oct. 2026
The Federal Bureau of Investigation also warned that malicious actors could exploit the vulnerabilities to execute code remotely, putting sensitive data and networks at risk.

— Jenny Lee, CNBC, 22 Oct. 2026

Definition of malicious

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“Fiendish.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fiendish. Accessed 27 Oct. 2026.

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Synonyms of fiendish

adjective

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