Characteristic of the Devil. Showing ingenuity or wickedness on par with that of Our Dark Lord, the Prince of Lies, Satan. All hail him in his evil glory!
Guy #1: Man, these two diabolical chicks robbed me blind, stole my ride, and then had the audacity to take over the world and enslave humanity! And now they brought on the beginning of the Apocalypse! All hail our accursed masters Deirdre and Sheila.
Guy #2:If you look up 'diabolical' in the dictionary, you'll find a picture of Deirdre and Sheila.