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

Relevance

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

But cultural myths and urban legends have also stereotyped them into Halloween mascots, demonic beings and carriers of diseases.

— Shi En Kim, AZCentral.com, 28 Aug. 2026
Wolf succumbs to Shura, a demonic force in the game’s mythology that possesses those who give in to bloodlust.

— Aman Kumar, Encyclopedia Britannica, 27 Aug. 2026

Definition of demonic

Adjective

Within a span of four months in Fort Worth last year, Watkins and Snellings were killed in similarly brutal attacks in the Near Southside and Historic Southside sections of the city.

— Emerson Clarridge, Fort Worth Star-Telegram, 28 Aug. 2026
Even so, when investor confidence broke in 1997, the adjustment was swift and brutal.

— MICHAEL PETTIS, Foreign Affairs, 28 Aug. 2026

Definition of brutal

Adjective

Julia, on the other hand, is forced to return to Castle Leathers and face her sinister husband, Lord Lovat (Tony Curran), who still believes that Julia’s child is his own.

— Max Gao, HollywoodReporter, 31 Aug. 2026
The longtime Adult Swim mischief-maker behind the viral hits ‘Too Many Cooks’ and ‘Yule Log’ specializes in hijacking familiar media formats, revealing the sinister anxieties beneath them.

— Carlos Aguilar, Los Angeles Times, 28 Aug. 2026

Definition of sinister

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

Your husband merely identified the obvious, most vicious enemy of the people in straightforward terms.

— Andy Andersen, Vulture, 30 Aug. 2026
Democrats have little trouble understanding that the right-wing infighting over Carlson is about whether the Republican tent, which already includes racists, nativists, and vicious Islamophobes, is also big enough to include anti-Semites.

— Jonathan Chait, The Atlantic, 28 Aug. 2026

Definition of vicious

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

Browse Nearby Words

fiend

fiendish

fiendishly

See all Nearby Words

Cite this Entry

Style

“Fiendish.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fiendish. Accessed 4 Sep. 2026.

Copy Citation

Synonyms of fiendish

adjective

Example Sentences

Browse Nearby Words

Cite this Entry

More from Merriam-Webster

Word of the Day

apiary

Popular in Grammar & Usage

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

A List of Most Commonly Confused Words

Why do we use apostrophes to show possession?

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?

Popular in Wordplay

The Longest Long Words List

Stay Woke

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

The Words of the Week - Sept. 4

Popular

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

The Longest Long Words List

Stay Woke

Games & Quizzes