The 'moutza' is the most traditional insulting gesture among Greeks. It consists of presenting your hand, fingers extended palm facing outward, to another person – as if to say 'stop'. An even more offensive version is achieved by using both hands, smacking the palm of one hand against the back of the other, thus doubling the gesture. The closer the gesture is to the victim's face, the more threatening. The gesture effectively means: 'eat shit!'
The 'moutza' stems from an ancient Byzantine practice whereby a chained criminal or prisoner of war was paraded around town and have his face spread with cinders, dirt and/or faecal matter to humiliate him. Cinders, in medieval Greek, were called 'moutzos'. And, because cinders were wiped onto the person's face by first collecting it in the palm and then spreading it with open fingers, this gesture itself became insulting and known as 'moutza' after the name of the material applied.
When the Greeks and the Romans were opponents, if Greeks captured Romans, they would pick up mud or faecal matter and rub it in the faces of the prisoners.
As with so many ancient gestures, a modern meaning has come to be associated with this gesture. This new meaning is of a sexual nature, whereby each finger is supposed to represent one of the sexual acts one intends to perform on the victim's sister...