Impiety is a lack of proper concern for the obligations owed to cult in its proper sense. Impiety was a main pagan objection to Christianity, for unlike other initiates into mystery religions, Christians refused to cast a pinch of incense before the images of the gods, among whom were the protective deified Emperors. Impiety was a civic concern, for it could bring down upon the whole res publica the wrath of the tutelary gods who protected the polis.
Sin was an alien concept to the Greeks and Romans. When Aramaic had to be translated into Greek in editing the New testament, the greek word hamartia came to be used. Hamartia ("missing the mark") is only very approximately translated as "sin."
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