What does anathema mean?
The definition of anathema
A*nath”e*ma, n.; pl. Anathemas.
Etym: [L. anath, fr. Gr. anath, fr. Gr. Thesis.]

1 A ban or curse pronounced with religious solemnity by ecclesiastical authority, and accompanied by excommunication. Hence: Denunciation of anything as accursed. [They] denounce anathemas against unbelievers. Priestley.
2 An imprecation; a curse; a malediction. Finally she fled to London followed by the anathemas of both [families]. Thackeray.
3 Any person or thing anathematized, or cursed by ecclesiastical authority. The Jewish nation were an anathema destined to destruction. St. Paul . . . says he could wish, to save them from it, to become an anathema, and be destroyed himself. Locke.Anathema Maranatha

Etym: (see 1 Cor. xvi. 22)

an expression commonly considered as a highly intensified form of anathema. Maran atha is now considered as a separate sentence, meaning, “Our Lord cometh.”