fiendish.
Sinister; evil; like a fiend.
Meaning & usage
Sinister; evil; like a fiend.
The detective was puzzled by the fiendish plot to steal the diamonds.
She had a fiendish smile that hinted at a cunning plan.
Very difficult.
The exam was filled with fiendish questions that made no sense.
a fiendish crossword puzzle
Where this word comes from
Etymology tree English fiend Proto-Indo-European *-iskos Proto-Germanic *-iskaz Proto-West Germanic *-isk Old English -isċ Middle English -isch English -ish English fiendish From fiend + -ish.
Try it on your idea.
fiendish has 8 characters. Say it out loud, try it alongside a description of your project, and see whether its meaning fits what you want to create.
These are naming prompts. Meanings and pronunciation can vary; existing brand and domain uses have not been checked.
Explore the name generatorA word with a source.
Definitions, grammatical labels, IPA, etymology and examples: Wiktionary contributors, extracted by Kaikki / Wiktextract. Adapted under CC BY-SA 4.0. Selected fields and authored examples are shown; third-party quotations and audio are omitted. See contributor history.
Last enriched 2026-09-10. Definitions are in English. Romanizations are shown when supplied by the source; syllable estimates are omitted for unsupported scripts.