adjective
- extremely cruel or wicked
- extremely difficult or challenging
Usage: informal
Examples
- The villain’s fiendish plot threatened the entire city.
- She gave him a fiendish grin before revealing her secret.
- The math problem was fiendish – nobody could solve it.
- His fiendish laughter echoed through the dark castle.
- The puzzle was fiendishly difficult to complete.
- The dictator’s fiendish cruelty shocked the world.
- That crossword is fiendish – I’ve been stuck for hours.