Fiendishly is a word that is used to describe someone who is very cruel and evil. They are usually obsessed with inflicting pain on others, and they enjoy it.
The villain was fiendishly cruel, tormenting the protagonist for fun.
The villain was fiendishly clever, managing to escape from the police station fiendishly.
adverb
as a devil; in an evil manner
Synonyms:
1
I know of your fiendish plans.
2
He transforms into a fiendish demon dragon.
3
This provides the sort of tense and fiendish gameplay.
4
Can they be allowed to continue their fiendish reign of terror
5
He is not a perfidious or barbarous or fantastically fiendish foe.
6
Halloween's fiendish fun translates into big bucks.
7
Most people might not be aware of is his fiendish love.
8
I had been duped by fiendish studio producers.
9
This halloween bash is perfect for inviting your fiendish friends.
10
He then chuckles at seeing the girl's fiendish gleam in her eyes.