Идио́т (от др.-греч. ἰδιώτης; idiōtēs — частное лицо).
Слово произошло от древнегреческого «идиотэс» — термина, определявшего человека, жившего в отрыве от общественной жизни, а также не участвовавшего в общем собрании граждан полиса (экклесия, апелла, агора, алия) и иных формах государственного и общественного демократического управления.
Т.е. не голосуешь, в общественной жизни не участвуешь? — в Греции тебя называли бы идиотом.
Точнее: идиот - человек, неспособный судить об общественных делах.
Idiot as a word derived from the Greek ἰδιώτης, idiōtēs ("person lacking professional skill", "a private citizen", "individual"), from ἴδιος, idios ("private", "one's own").
An idiot in Athenian democracy was someone who was characterized by self-centeredness and concerned almost exclusively with private — as opposed to public—affairs. Idiocy was the natural state of ignorance into which all persons were born and its opposite, citizenship, was effected through formalized education. In Athenian democracy, idiots were born and citizens were made through education (although citizenship was also largely hereditary). "Idiot" originally referred to "layman, person lacking professional skill", "person so mentally deficient as to be incapable of ordinary reasoning". Declining to take part in public life, such as democratic government of the polis (city state), was considered dishonorable. "Idiots" were seen as having bad judgment in public and political matters.