Skip to main content
fiendishly

fiendishly

5 9.1
In a very cruel, very clever, or very difficult way
  • adverb
  • /ˈfiːndɪʃli/
translation icon : diabólicamente
  • Solving the puzzle was fiendishly difficult, leaving even the experts scratching their heads.
  • fiendishly clever
  • fiendishly complicated
  • fiendishly difficult

And it's been fiendishly difficult because there are some species such as the little brown bat.

Autoplay Next

Examples

  • And it will have to be a fiendishly clever plan.

  • Finally, can you handle the course's fiendishly difficult terrain?

  • Not to say it's not worth doing, but it's fiendishly complex.

    Blog text (18)
  • When you first look at this, you think it's a free lunch, but in fact it's fiendishly complicated.

    Fiction book (1991)
  • It's the most fiendishly difficult country to negotiate with.

  • Each one is more fiendishly clever than the last.

  • The kid's plan was fiendishly clever.

  • Particle physics has pinned its hope on string or membrane theories that are elegant but fiendishly difficult to decipher.

    Academic text (2004)
  • Among the trickiest errors to deal with are so-called systematic biases, which skew temperature measurements in fiendishly complex ways.

    Blog text (24)
  • The magician devised a fiendishly clever trick that left the audience in awe.

Synonyms

wickedly
vsfiendishly
5 6.3

In an evil and cruel way that harms other people

extends this by also implying extreme clever or fiendish manner
monstrously
vsfiendishly
5 6.8

In a very cruel and shocking way

focuses more on sly wicked cleverness than sheer monstrous quality
evilly
vsfiendishly
4 8.4

In a cruel way to hurt or frighten others

can also mean clever mischief or devilish cleverness, not just evil
diabolically
vsfiendishly
3 8.4

In a very evil way

can mean cruel cleverness rather than only outright evil
devilishly
vsfiendishly
2 7.2

In a playful, slightly naughty way that shows mischief

is more extreme cruelty or wickedness, not playful cleverness
hellishly
vsfiendishly
2 8.8

In a very intense and unpleasant way

leans more toward cunning, clever cruelty than mere intensity
heinously
vsfiendishly
  • Formal
1 8.4

To do something in a very shocking and cruel way

is similar but can emphasize cunning cleverness over shock value
satanically
vsfiendishly
1 8.9

In a very evil way

adds the idea of cunning cleverness alongside sheer evil
malevolently
vsfiendishly
  • Formal
1 8.6

In a way that shows a wish to hurt others

adds a sense of clever wickedness rather than only desire to harm
demonically
vsfiendishly
  • Literature
1 8.2

In a way that seems evil, wild, and frightening

includes clever wickedness as well as fierce, deliberate cruelty
twistedly
vsfiendishly
  • Informal
9.1

In a cruel way showing pleasure at others' pain

adds an element of cleverness or fiendlike clever planning
unholily
vsfiendishly
9.7

In a rude way about religious things

focuses more on clever wickedness resembling a fiend rather than impiety
villainously
vsfiendishly
  • Informal
7.3

To a very high degree

carries real evil or clever cruelty rather than mere emphasis

Antonyms

372 1.0

To do something with little force to avoid hurting or making noise

179 1.0

In a gentle and caring way

How Wicked

diabolically
3 8.4
fiendishly
5 9.1
wickedly
5 6.3
cruelly
16 3.0
meanly
1 7.0
unkindly
4 4.4

Surface Forms

fiendishly positive

Morphology

fiendishly = fiendish (semi-transparent) = fiend + ish + ly

While the base 'fiend' is clear, the meaning of 'fiendishly' extends beyond the literal sense to include cleverness, which may not be immediately apparent.

Etymology

The word fiendishly comes from fiend, an old word meaning 'enemy' and later 'devil', plus the ending -ishly, which means 'in the manner of'. So when something is done fiendishly it is done like a devil: cruel, wicked, or extremely clever.