In Classical Athens, there was no exact equivalent of the English term "adultery", but the similar moicheia (Ancient Greek: μοιχεία) was a criminal offence often translated as adultery by scholars. Athenian moicheia was restricted to illicit sex with free women, and so men could legally have extra-marital sex with slaves and prostitutes. Famously, Athenian culture and adultery laws considered seduction of a citizen woman a worse crime than rape.
Under Athenian law, killing a moichos who had been caught in the act was legally permissible as justifiable homicide. This seems to have been rare in practice, and adulterers were more commonly prosecuted, ransomed for money, or physically abused. The physical abuse and humiliation of adulterers is depicted in several surviving ancient Greek comedies. Punishments for women involved in moicheia include divorce and the loss of citizenship rights, if they were married, and being sold into slavery, if unmarried – though no instances of this latter penalty being carried out are known.