Anathema shows up five times as a noun in the New Testament (Rom 9:3; 1 Cor 12:3, 16:22; Gal 1:8, 9) and oddly, one time as a verb (Acts 23:14). It is a strange, foreign-sounding word that has an oddly long life. For example, if you read the canons of the Council of Trent, each stated idea condemned by the Council is followed by “…anathema sit” or “let him be anathema [if he holds this view]. See the section on justification, for example. There’s even a joke about a Catholic monsignor who named his dog “Anathema,” so that he could yell at the dog, “Anathema sit!”
Often, the New Testament examples of “anathema” are translated as “accursed.” So, for example, in Gal 1:9 Paul teaches, “If anyone is preaching to you a gospel contrary to the one your received, let him be accursed” (ESV). The word there really is “anathema.”
The word does show up in the Septuagint 26 times (Lev 27:28 twice; Num 21:3; Deut 7:26 twice, 13:16, 13:18, 20:17; Josh 6:17, 6:18 thrice, 7:1 twice, 7:11, 7:12 twice, 7:13 twice, 22:20; Judg 1:17; 1 Chr 2:7; Judith 16:19; 2 Macc 2:13, 9:16; Zech 14:11). In these Old Testament references, “anathema” often refers to something “devoted” to the Lord (Lev 27:28; Josh 6:17), but it can refer to things that are cursed (Deut 7:26). Oddly, the word is used as a proper noun for a place name in Hebrew, “Hormah,” but in Greek, “Anathema” (Num 21:3; Judg 1:17). However, this is more a translation than a transliteration. The word “Hormah” is derived from the Hebrew verb hrm which means to devote something.
Ok, so what does anathema mean? Well, it comes from the Greek verb, anatithemi, which means to “lay upon” and therefore “refer, attribute, ascribe, entrust, commit, set up, set forth, declare.” The idea is that you might put an offering of some kind before a person or god, laying it upon an altar or perhaps at the feet of another.This verb actually shows up in Acts 25:14 and Gal 2:2, where a person “lays” a matter before another; in one case Festus lays Paul’s case before Felix, in the other, Paul lays his views before the apostles. So “anathema” means a “thing laid before” or a “thing devoted.” It translates the Hebrew word herem in the Old Testament, which as we saw above could refer to something devoted to God or something devoted “to destruction,” an abominable thing. So in light of the Septuagint, the New Testament uses of anathema follow in the second track, using “anathema” to mean “accursed” or “abominable.” The Liddell-Scott-Jones Lexicon does not offer a lot of help. Moulton-Miligan’s Vocabulary of the Greek New Testament (p. 33) expound on the Megara inscription mentioned by LSJ, which actually reads “anethema”, and they explain the spelling difference but translate the word as “curse!” The Thesaurus Linguae Graecae shows 1753 results for “anathema”, but most are post-New Testament. It seems to be a word that came into its own in the Septuagint and then used in the NT with it’s “septuagintal” sense of “accursed.”