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

The better to act out empire’s idea of what disgusting demonic sickness looks like.

— Literary Hub, Literary Hub, 15 Sep. 2026
Around his ankle is a heavy plastic GPS tracking device, with a red, LED status light glaring like a demonic eye.

— Philip Kennicott, Washington Post, 5 Sep. 2026

Definition of demonic

Adjective

Thirty-two years after Brown Simpson's brutal killing, her sister continues to alert people to the dangers of intimate partner violence.

— Emily Shapiro, ABC News, 2 Oct. 2026
The Trojans face Washington at the Coliseum before a brutal stretch that includes Penn State, Indiana and Ohio State, with their playoff hopes at stake.

— Ryan Kartje, Los Angeles Times, 2 Oct. 2026

Definition of brutal

Adjective

Things are just a little less sinister in the song’s lyrics than in the way things play out on screen.

— Chris Willman, Variety, 28 Sep. 2026
As the first three episodes unfold, the number keeps appearing in increasingly sinister ways — ultimately helping connect the season’s seemingly disparate characters and storylines.

— Lexi Carson, HollywoodReporter, 25 Sep. 2026

Definition of sinister

Adjective

In the book, MacLachlan recalls being utterly dumbfounded at having been asked to do something so oblivious at best and cruel at worst.

— Rachel Brodsky, Los Angeles Times, 25 Sep. 2026
Many of them, including Ned and his childhood friend and rival, Roland, are scarred by their time as youth players, haunted by memories of the sadistic coaches and cruel, competitive fathers who terrorized them both on and off the court.

— Literary Hub, Literary Hub, 24 Sep. 2026

Definition of cruel

Adjective

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
Of course, in this case Megatron isn't the diabolical leader of the Decepticons who killed Optimus Prime in the Transformers franchise, but the most detailed simulation to date of the early universe.

— Robert Lea, Space.com, 2 Oct. 2026

Definition of diabolical

Adjective

The film focuses on a psychological experiment that Kaczynski was part of in college, where he was subjected to vicious personal attacks.

— K. Thor Jensen, PC Magazine, 25 Sep. 2026
In the clip, an 11-year-old Breakers player can be seen skating up the ice before delivering a vicious, two-handed slash to the head of a Kings player.

— Matt Reigle OutKick, FOXNews.com, 22 Sep. 2026

Definition of vicious

Adjective

Once installed, the malicious app pushes you to enable Android's Accessibility service.

— Kurt Knutsson, FOXNews.com, 2 Oct. 2026
Companies should detect prompt injection, malicious or compromised tools, behavioral anomalies, data exfiltration and other threats.

— Shashwat Sehgal, Forbes.com, 1 Oct. 2026

Definition of malicious

Adjective

The Philadelphia Semiconductor Index weathered a savage 30% drawdown, has been choppily trendless for two months, then in recent days finally broke above its downtrend and surmounted the 50-day moving average.

— Michael Santoli, CNBC, 22 Sep. 2026
Hamilton lets down Claire’s savage hauteur; Mays’ eyes glisten with all the regrets of lost love.

— Theater Critic, Los Angeles Times, 16 Sep. 2026

Definition of savage

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“Fiendish.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fiendish. Accessed 5 Oct. 2026.

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Synonyms of fiendish

adjective

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