fiendishly
fien-dish-ly
adverb
Extremely difficult, cruel, or cunning, often in a wicked or challenging way.
"The crossword puzzle was fiendishly difficult."
Thesaurus
Synonyms: devilishly, diabolically
fien-dish-ly
Extremely difficult, cruel, or cunning, often in a wicked or challenging way.
"The crossword puzzle was fiendishly difficult."
Synonyms: devilishly, diabolically