What does diabolical mean?
Diabolical is an adjective with two main uses. In its original and more formal sense, it describes something wicked, cruel, or fiendishly evil — the kind of behaviour attributed to the devil — as in a villain's diabolical plan. It derives from the Greek diabolos, meaning 'slanderer' or 'devil', and entered English in the sixteenth century. In everyday speech, particularly in British English, diabolical has also taken on a milder, hyperbolic meaning: simply very bad or appalling. A footballer might have a diabolical first half, and commuters routinely describe the weather or train service as diabolical without any implication of genuine evil. This shift from the infernal to the merely incompetent gives the word its distinctive range, allowing speakers to move between serious condemnation and comic exaggeration. Its adverb form is 'diabolically'.
Of, relating to, or characteristic of the devil; extremely wicked or evil.
"The novel's antagonist devises a diabolical method of disposing of his victims."
This sense is often used figuratively for schemes or cruelty rather than literal demonism.
(Informal, especially British) Extremely bad or unpleasant; appalling.
"We abandoned the picnic — the weather turned absolutely diabolical."
Common in colloquial British English; less frequent in American usage.
When British speakers complain that 'the traffic is diabolical,' they're literally calling it devilish — a 16th-century word for the demonic now applied to bad weather and poor service.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of diabolical
Diabolical comes from Latin diabolicus, which itself derives from Greek diabolos, meaning 'slanderer' or 'accuser' — the term used in the Greek Bible to translate 'Satan' and the source of the English word 'devil'. The adjective entered English via French in the early modern period, around the late sixteenth century. Related forms include the shorter variant 'diabolic' and the noun 'diabolism', all sharing the same Greek root.
Related word forms
How diabolical is actually used
The literal 'devilish' sense is somewhat formal or literary. The informal British sense meaning 'terrible' or 'appalling' is very common in everyday speech, particularly regarding weather, service, or performance. The word carries strong negative connotation in both senses.
Easily confused with diabolical
'Symbolical' means serving as a symbol or sign, whereas 'diabolical' means devilish, evil, or (informally) terrible.