Diabolical means of, relating to, or characteristic of the devil, and by extension extremely evil, cruel or wicked. In British informal English it also carries a milder sense of very bad, awful or disgraceful, as in diabolical weather or diabolical service.
Core meaning
At its heart, diabolical describes something devilish. It can refer literally to the devil, as in diabolical lore, or figuratively to actions, plans and people that are wicked in a deliberate, calculated way. A diabolical plot suggests scheming that is not just bad but sinister.
The informal British sense
In everyday British and Irish speech, diabolical is often used as a strong way of saying terrible. Someone might complain that the traffic was diabolical or that a performance was diabolical. Here the word has drifted from evil toward simply awful or unacceptable.
Diabolical used approvingly
Occasionally diabolical is paired with a word like clever or ingenious to describe something impressively cunning. A diabolically clever puzzle is fiendishly difficult in a way the speaker admires, showing how the word can shade from condemnation toward grudging respect.
Grammar and related forms
Diabolical is an adjective. Its adverb form is diabolically, and the closely related adjective diabolic carries much the same meaning. All of these words share the theme of the devil or devil-like behavior.
Origin
The word travels back through Latin diabolus to the Greek diabolos, which literally means slanderer or accuser. That Greek root is also the source of the word devil itself, which explains why diabolical and devilish sit so close together in meaning.
Example sentences
The villain devised a diabolical scheme to seize the throne. The customer service was absolutely diabolical. She solved the diabolically difficult riddle in seconds. Each example shows a different shade of the same core idea, from genuine evil to plain awfulness to admiring exaggeration.
Frequently Asked Questions
What does diabolical mean?
It means devilish or characteristic of the devil, and by extension extremely evil or wicked.
Can diabolical just mean very bad?
Yes. In British informal usage it often means terrible or disgraceful, as in diabolical weather.
Where does the word diabolical come from?
It derives from Latin diabolus, from Greek diabolos, which literally means slanderer.
What is the adverb form of diabolical?
The adverb is diabolically, as in a diabolically clever plan.
Is diabolical always negative?
Generally yes, though it is sometimes used admiringly for something impressively cunning, as in diabolically clever.