Part of speech:
Appropriate to a devil, especially in degree of wickedness or cruelty.
Of, resembling, or suggestive of a devil; fiendish:
Appalling or dismaying
Characterized by savagery; very cruel:
Very great; extreme
Not easy to comprehend, solve, or explain:
Characterized by or indicating future misfortune; ominous:
Of, characteristic of, or like Satan; devilish; infernal; diabolic
Causing or intending harm or evil; wicked:
Having bad or harmful habits; unruly
Extremely or ingeniously difficult, vexatious, etc.; fiendish
Very unpleasant; detestable
Find another word for fiendish. In this page you can discover 21 synonyms, antonyms, idiomatic expressions, and related words for fiendish, like: diabolical, demoniac, infernal, cruel, wicked, atrocious, barbarous, demonic, devilish, difficult and evil.