1. the quality or state of being diabolical; extreme wickedness or evil
Usage: abstract noun derived from the adjective 'diabolical'

Examples

• The diabolicalness of the villain's plan shocked everyone in the courtroom.
• She was struck by the sheer diabolicalness of his betrayal.
• The diabolicalness of the scheme became apparent only after months of investigation.
• No one could deny the diabolicalness of such a cruel and calculated act.
• The novel explores the diabolicalness lurking beneath an ordinary facade.