anathema (n.)
1520s, "an accursed thing," from Latin anathema "an excommunicated person; the curse of excommunication," from Greek anathema "a thing accursed," originally "a thing devoted," literally "a thing set up (to the gods)," from ana- "up" (see ana-) + tithenai "to put, place" (see theme).

Originally simply a votive offering, by the time it reached Latin the meaning had progressed through "thing devoted to evil," to "thing accursed or damned." Later applied to persons and the Divine Curse. Meaning "formal act or formula of consigning to damnation" is from 1610s.

Anathema maranatha, taken as an intensified form, is a misreading of the Syriac maran etha "the Lord hath come," which follows anathema in I Cor. xvi:22, but is not connected with it (see Maranatha).