In a diabolic manner; in an extremely wicked or cleverly evil way.
Formed by adding the -ly adverbial suffix to diabolic, following English word-formation patterns. This allows the adjective to describe how an action is performed.
The -ly suffix is one of English's most productive morphemes, transforming any adjective into an adverb—it comes from Old English -lice meaning 'in the manner of,' literally 'like.'
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