Meanings
-
1
adv
In an evil or wicked way.
The guards grinned fiendishly as they locked the prisoners in their cells.
-
2
adv
Extremely (often before a difficult or unpleasant quality).
The new safe was fiendishly hard to crack.
Thesaurus
Synonyms
More
diabolically
Word family
Etymology
From fiendish + -ly.