This state of being entirely removes any rights or privileges one would have as a priest and is used to cast out those who would otherwise dishonour the church by assosciation.
Scholar 1: "The public ceremony was a key part of punishment for high crimes during the medieval period. For example, one would have the flesh stripped by hot pincers, then have a molten lead, sulfur cocktail poured into the open wounds, how horrible!"
Scholar 2: "Quite right my chap, but imagine the pain and anguish that would come with being depriestified in a time where so much relied on your status."
Scholar 1: "Is depriestified even a word?"
Scholar 2: "It is at UW."
Smart Ass Scholar: "I'll put it on Urban dictionary later."
Scholars 1 and 2: "Quite right!"