fiendish is a valid English word

Scrabble validity: valid ( international - Sowpods, US - Twl06 )
iScramble validity: valid
QuickWords validity: valid

Meanings

Adjective (COMPARABLE)

Sinister; evil; like a fiend.
• Synonym: conniving
Very difficult.
• a fiendish crossword puzzle

fiendish is a Scrabble valid word

fiendish

• International English (Sowpods) - The word is valid in Scrabble ✔
• US English (TWL06) - The word is valid in Scrabble ✔
• 00 points

fiendish is an iScramble, QuickWords valid word

fiendish

• The word is valid in iScramble ✔
• The word is valid in QuickWords ✔
• 00 points

Same letters words (Anagrams)

• FINISHED

Same letters plus one

• DEFISHING
• FIENDSHIP
• FRIENDISH
• SHINFIELD

Same letters minus one

• FINEISH