Machiavelian \Mach`i*a*vel"ian\, a. [From Machiavel, an Italian writer, secretary and historiographer to the republic of Florence.] Of or pertaining to Machiavel, or to his supposed principles; politically cunning; characterized by duplicity or bad faith; crafty. Machiavelian \Mach`i*a*vel"ian\, n. One who adopts the principles of Machiavel; a cunning and unprincipled politician.