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

Dorinda’s residence is perhaps the single most iconic location in all of Housewifery because that demonic energy caused friction in every single interaction that took place there.

— Brian Moylan, Vulture, 5 Oct. 2026
The better to act out empire’s idea of what disgusting demonic sickness looks like.

— Literary Hub, Literary Hub, 15 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

Swift appears as a spectral figure trying to warn Johnson that, based on her own experience, her rich husband has more sinister intentions than his current bride imagines.

— Chris Willman, Variety, 4 Oct. 2026
And with its peaks and sharp angles, the home could morph from architectural wonder in the daylight to something more sinister in the shadows of the night.

— Juliet Izon, Architectural Digest, 2 Oct. 2026

Definition of sinister

Adjective

The policy of sending them to a third country has been condemned as harsh and cruel.

— Los Angeles Times, Los Angeles Times, 4 Oct. 2026
Eight men were killed via gassing until an Alabama district judge ruled the execution method unconstitutionally cruel, in June; the Supreme Court has maintained the block.

— Doreen St. Félix, New Yorker, 3 Oct. 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

Experts are voicing concerns over the vicious cycle of rising debt and higher yields.

— Lee Ying Shan, CNBC, 5 Oct. 2026
Verity dwells almost entirely in the gulf between the front-facing celeb being interviewed by Alex Cooper and the vicious private thoughts of her confession.

— Bethy Squires, Vulture, 5 Oct. 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 Indian pilot who fought off a savage attack by his copilot and helped prevent an apparent hijack of a Flydubai plane heading to Israel with more than 170 people on board is being hailed as a hero.

— Rhea Mogul, CNN Money, 1 Oct. 2026
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

Definition of savage

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“Fiendish.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fiendish. Accessed 8 Oct. 2026.

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Synonyms of fiendish

adjective

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