The inspiration for this post is drawn from 666's blog which had a small snippet on Lucrezia Borgia whose family was famed for their Machiavellian politics during the Renaissance papacy. She was the daughter of Pope Alexander VI which has me a little confused since I always thought celibacy was an important criteria for occuping the highest post of the Vatican. Her marriages were arranged to men of importance and duly terminated in a vicious manner once they ceased to be of any use to the Pope.
Coming back to the term which means someone characterized by subtle or unscrupulous cunning, deception, expediency, or dishonesty. Machiavellianism is primarily the term some social and personality psychologists use to describe a person's tendency to deceive and manipulate others for personal gain.
The concept is named after Renaissance diplomat and writer Niccolò Machiavelli, who wrote Il Principe (The Prince), in which political expediency is placed above morality and the use of craft and deceit to maintain the authority and carry out the policies of a ruler is described.
Sources : http://en.wikipedia.org, http://sixsixsixx.blogspot.com/