This is a Christian term for a person who has been officially cast out or excommunicated. It supposedly was derived from 1 Corinthians 16:22 «If any man love not the Lord Jesus Christ, let him be Anathema Maranatha.» Originally it was a curse pronounced by the goddess Marah or Mari-Anath on her dying god.
During medieval times Anathema in Christianity meant to be castigated from the congregation with the ritual of Book, Bell, and Candle, and irrevocably condemned to hell. This is a curious reminiscence of an accused god’s temporary descent into the underworld, in ancient religions. A.G.H.
Source: 56, 32.