fiendish

/ˈfiːndɪʃ/

//ˈfiːndɪʃ// adj

By · According to Wiktionary data (CC BY-SA) ·

"fiendish" is a 8-letter English headword indexed on PlainSpell.

The verdict

“fiendish” is uncommon English (frequency #55,435 among 2,507 “F” headwords), classed as an adjective. The kind of spelling people second-guess.

#55,435
frequency rank, English
2,507
“F” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Sinister; evil; like a fiend.

Corpus desk

Index EN-fiendish · fiendish · English

fiendish · rank #55,435 · 0 variants · 0 confusables

  • FREQ-RARE #55,435
  • LEN-LONG 8 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,507
  • PHOTO-FINISH fila

Nearest frequency peer: fila (+1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “fiendish”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “fiendish” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for fiendish
PropertyValue
Headwordfiendish
LanguageEnglish
Part of speechAdjective
IPA/ˈfiːndɪʃ/
Letters8
Frequency rank#55,435
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “fiendish” in English

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).fiendishfalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “fila” (#55,436), “ferociously” (#55,433), “finery” (#55,437). Among 2,507 “F” headwords, “fiendish” is #55,435. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

fiendish is uncommon English at frequency #55,435 among 2,507 “F” headwords, classed as anadjective, transcribed /ˈfiːndɪʃ/. Rarity is why readers land here mid-draft. 2 senses are on record.

Zero misspellings are on record for fiendish in our index, a sign its spelling follows regular English conventions. This headword has no recorded confusable partner, which typically means the spelling is too distinctive to be mistaken for another word.

Etymologically, the entry records: From fiend + -ish. The correct English form is fiendish, spelled F-I-E-N-D-I-S-H.

Definition

  1. 1
    Sinister; evil; like a fiend.
  2. 2
    Very difficult.

Recorded use

Wiktionary examples

These source excerpts show how fiendish appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. The detective was puzzled by the fiendish plot to steal the diamonds.
  2. She had a fiendish smile that hinted at a cunning plan.

Etymology

From fiend + -ish.

This word in other languages

diabólico(Español)diabolique(Français)teuflisch(Deutsch)sinistro(Português)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "fiendish"?
"fiendish" is spelled F-I-E-N-D-I-S-H. The IPA pronunciation is /ˈfiːndɪʃ/.
What does "fiendish" mean?
As an adjective, "fiendish" means: Sinister; evil; like a fiend.
How do you pronounce "fiendish"?
The IPA (International Phonetic Alphabet) transcription for "fiendish" is /ˈfiːndɪʃ/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "fiendish"?
From fiend + -ish. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "fiendish", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 8 letters (nearest by frequency rank).

furrowed#55,447Eurostar#55,418glycemic#55,461grossest#55,471

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list