The principal conspirator or the most cunning schemer in a plot; the mastermind behind a conspiracy.
Arch- plus plotter (from plot, possibly from Old Norse and meaning to map out or scheme). The term gained currency in Early Modern English during an era of famous conspiracies and court intrigues.
Historical texts used 'archplotter' to describe figures like Cardinal Richelieu or Thomas Cromwell—men accused of secretly orchestrating complex political schemes from behind the scenes.
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