Anathema (Gr. Anathema 100290 from Anathema 100291 I set apart), in the Greek classics, anything set apart as an offering to the gods, applied to the numerous votive gifts which were suspended upon the walls of temples or exposed upon public altars. By change of usage it afterward became the name of anything devoted to the infernal gods, anything execrated and execrable, causing the abhorrence of men. In this sense it was adopted by the Christian church as the synonyme of the Hebrew 'herem, which signifies both a thing devoted to God and extermination, and which was used by the Jews in pronouncing the ban of excommunication. The Old Testament gives many examples of 'herem or anathema. Moses pronounced the anathema against those Canaanitish cities which should refuse to submit to the Lord, and Joshua declared everything captured in Jericho 'herem, and punished Achan for violating the ban. In the New Testament it is used in the sense of "set aside" or "accursed." In the Roman Catholic church it is a sentence pronounced against heretics and schismatics, or against those who wilfully and obstinately persevere in a course of conduct which the church condemns.

It implies exclusion from the communion and society of the faithful, who are taught to regard the object of this ecclesiastical penalty as one who by his crimes has cut himself off from the church and merited the flames of hell. The anathema, however, is not supposed to be a sentence of eternal reprobation; it is a temporal punishment, similar in its effects to excommunication. Most of the dogmatical decrees of the church close with anathemas against all who presume to deny them. Thus the council of Trent employs it against such as deny the existence of purgatory, the doctrine of the real presence, etc.