fiendish
Americanadjective
adjective
-
of or like a fiend
-
diabolically wicked or cruel
-
informal extremely difficult or unpleasant
a fiendish problem
Other Word Forms
- fiendishly adverb
- fiendishness noun
Etymology
Origin of fiendish
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
To make up for it, he pulled out a completely different jumping pass on the fly, starting with a different quad—-and then landed another fiendish combination.
From The Wall Street Journal • Feb. 9, 2026
That is good news for Inter who have a fiendish run of fixtures to close their league phase campaign, including clashes at the San Siro with Liverpool and Premier League leaders Arsenal.
From Barron's • Nov. 5, 2025
Atencio’s fiendish feline would have followed guests throughout the ride, a creature said to despise living humans and with predatory, possessive instincts.
From Los Angeles Times • Nov. 5, 2025
The only advice Ms Keast-Butler gave BBC Breakfast earlier on Wednesday was to work in a team and "bring a rich mix of minds" to the fiendish puzzle.
From BBC • Dec. 11, 2024
Clyde’s fiendish mind has not stopped at so simple an abasement, however.
From "A Confederacy of Dunces" by John Kennedy Toole
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.