Defrocking

To defrock a priest is to deprive him of the right to exercise the functions of the priestly office. Various religions with priests have different procedures for doing this.

Roman Catholicism

The Council of Trent (session XIII, canon iv) declared that ordination, being a sacrament, imbues the recipient with an indelible "priestly character". Therefore the return of an ordained priest to the lay state is absolutely impossible. However, “laicization”, which takes from a priest the licit use of his powers, and other rights, can occur by various means.

A priest is automatically laicized when he marries or joins the military without permission. A priest may be voluntarily laicized by his superiors at his request. A priest may be involuntarily laicized for wrongdoing. Minor clerics, including priests, are laicized through the "penalty of degradation". Major clerics can be laicized by the Holy See.

Laicized priests are forbidden to wear clerical habit, identify themselves as priests, or administer the sacraments. They are required to continue practicing celibacy, although dispensations can be made. By laicization a priest loses the right of benefice, which in modern times means he will not be supported by the Church even after retirement.

A laicized priest still has the power to confect the Eucharist but cannot use it licitly.