Mountza

It consists of extending and spreading all fingers of the hand and presenting the palm towards the face of the person to be insulted with a forward motion.

[1] When Greeks hand-signal the number 5 to someone they take care not to overextend the fingers or face their palm towards the person, lest it be mistaken for a mountza.

In the penal code of the Byzantine Empire one punishment entailed criminals paraded around town sitting backwards on a donkey with their face smeared with cinder (μούντζος, moútzos) to enhance their ridicule.

[3][4] Because cinder was wiped on the person's face first by collecting it in the palm and then by extending open the fingers, the gesture itself became insulting, to be known as mountza, after the name of the material applied.

[3][4] The modern Greek word mountzoura (μουντζούρα) or moutzoura (μουτζούρα) for a smudge, scribble or dark stain has the same origin.