English
fiendful
From fiend + -ful.
Formed from fiend + -ful
Proto-Indo-European *peh₁- ‘to hate’
Proto-Germanic *fijandz ‘enemy, fiend’
Proto-West Germanic *fijand
Old English fēond ‘enemy’
Middle English fend ‘enemy’
English fiend
Today it means
adj Full of fiendish arts or spirit.
Language periods are conventional ranges, not dates for this word.
Etymograph / fiendful