fiendishly

/ˈfiːndɪʃli/

//ˈfiːndɪʃli// adv

"fiendishly" is a 10-letter English headword indexed on PlainSpell.

The verdict

“fiendishly” is uncommon English (frequency #91,500 among 2,507 “F” headwords), classed as an adverb. The kind of spelling people second-guess.

#91,500
frequency rank, English
2,507
“F” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - In a fiendish manner; evilly, wickedly.

Corpus desk

Index EN-fiendishly · fiendishly · English

fiendishly · rank #91,500 · 0 variants · 0 confusables

  • FREQ-RARE #91,500
  • LEN-MEGA 10 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,507
  • PHOTO-FINISH fibrotic

Nearest frequency peer: fibrotic (-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 “fiendishly”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for fiendishly
PropertyValue
Headwordfiendishly
LanguageEnglish
Part of speechAdverb
IPA/ˈfiːndɪʃli/
Letters10
Frequency rank#91,500
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “fiendishly” 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).fiendishlyfalls in this rarity band:

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

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “fibrotic” (#91,499), “Filson” (#91,501), “fennec” (#91,495). Among 2,507 “F” headwords, “fiendishly” is #91,500. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

fiendishly is uncommon English at frequency #91,500 among 2,507 “F” headwords, classed as anadverb, transcribed /ˈfiːndɪʃli/. Rarity is why readers land here mid-draft. 2 senses are on record.

fiendishly doesn't appear in our generated misspelling index, a sign its spelling follows regular English conventions. It is not paired with a close-neighbour confusable in our dataset, which typically means the spelling is too distinctive to be mistaken for another word.

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

Definition

  1. 1
    In a fiendish manner; evilly, wickedly.
  2. 2
    Extremely, very in harsh or negative contexts.

Recorded use

Wiktionary examples

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

  1. At a side door, reclined on a couch, two guards of the haram, with their naked swords grasped in their hands, and features, fiendishly contorted between sleep and dissolution, seemed to menace death to any who should venture to approach.
  2. […] I was suddenly awakened by a savage looking fellow standing close to my bedside, ordering me and my companion to leave our bed forthwith or suffer the consequences; at the same time using the most blasphemous language, and uttering the most hideous oaths imaginable, while fiendishly striking his huge fists in close proximity to my face.

Etymology

From fiendish + -ly.

Synonyms

This word in other languages

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 "fiendishly"?
"fiendishly" is spelled F-I-E-N-D-I-S-H-L-Y. The IPA pronunciation is /ˈfiːndɪʃli/.
What does "fiendishly" mean?
As an adverb, "fiendishly" means: In a fiendish manner; evilly, wickedly.
How do you pronounce "fiendishly"?
The IPA (International Phonetic Alphabet) transcription for "fiendishly" is /ˈfiːndɪʃli/. 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 "fiendishly"?
From fiendish + -ly. 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 "fiendishly", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 10 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list