Machiavellian refers to a person who is cunning, manipulative and deceitful in their actions. It originates from the name of Niccolo Machiavelli, an Italian philosopher and writer who wrote about political power and influence in his book "The Prince". In this book, he advocated for ruthless tactics to maintain control, which included lying, cheating, and using violence if necessary. As a result, the term "Machiavellian" has come to describe someone who employs such strategies in their dealings with others.