Related topics: Law
ex post fac·to law /ˌeks pəʊst ˈfæktəʊ ˌlɔː $ -poʊst ˈfæktoʊ ˌlɒː/ noun [countableC] law SCLa law that makes a particular action into a crime, and then punishes people who took that action before it had legally become a crime 有追溯效力的法律