underhanded person; Machiavellian schemer
Refers to someone who uses cunning, behind-the-scenes tactics, often in politics or business. The term originally comes from judo, where 寝技 (newaza) are ground techniques, implying a person who works from a hidden or disadvantaged position.
He is known as a behind-the-scenes operator in the political world.
Be careful not to be deceived by that schemer.
陰謀家 explicitly means 'conspirator' and focuses on plotting, while 寝業師 emphasizes cunning manipulation in a broader sense, often in organizational contexts.
Formed from 寝業, which also means covert maneuvering or behind-the-scenes tactics, and 師, denoting a skilled practitioner. The figurative sense describes someone adept at secretive political or personal scheming.