What does "fiendishly" mean?
In a fiendish manner; evilly, wickedly.
adv ·Rare ·Advanced level
This entry combines structured lexical data with WordToolSet review checks. Definitions, examples, synonyms, and usage notes may come from different source tables, so the page is designed to show evidence from more than one angle before you rely on "fiendishly" in a final draft.
If a word has several senses, prefer the sense that matches your sentence's grammar and surrounding context. A correct definition can still be the wrong choice when the sentence needs a different register, emphasis, or level of specificity.
Read the first definition as a starting point, then check the example, synonyms, and part of speech before treating "fiendishly" as the right word for your sentence.
If your draft is formal, technical, persuasive, or sensitive, compare "fiendishly" with a nearby alternative so the final choice matches both meaning and reader expectation.
Check whether "fiendishly" is acting as adv in your sentence. A definition is only useful when the grammar matches the way the word is being used.
Compare it with "devilishly" and other nearby choices to see whether the sentence needs a softer, stronger, or more familiar word.
Use the example sentence below as an evidence check, then read your own sentence out loud to catch tone or rhythm problems.
Review note: Definition pages are checked for source coverage, sentence evidence, synonym support, and editorial insight before they are treated as approval-ready pages. If the evidence is too thin, the page remains available to users but is kept out of the approval-facing indexed inventory.
Before publishing a sentence with "fiendishly", ask whether the word helps the reader understand the idea faster. A precise word should reduce confusion, not simply make the sentence look more polished.
When the definition, synonym evidence, and example context point in the same direction, the word is usually a safer choice. When they conflict, revise the sentence or choose a clearer alternative.
"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."
"Either the Russians are so fiendishly clever that they've managed to keep one of their agents running in this organization for over twenty years or they're so fiendishly clever that they're sending us false defectors to claim that they have."
"His long, claw-like fingers danced from one part of the machine to another fiendishly, and a hideous grin distorted his features."
In a fiendish manner; evilly, wickedly.
Common synonyms include: devilishly, diabolically, atrociously, cruelly, devilishly, diabolically.
His long, claw-like fingers danced from one part of the machine to another fiendishly, and a hideous grin distorted his features.
Pronounced /ˈfiːndɪʃli/.
From fiendish + -ly.