Anathema!

a·nath·e·ma /ənæθəmə

–noun, plural -mas.
1. a person or thing detested or loathed: That subject is anathema to him.
2. a person or thing accursed or consigned to damnation or destruction.
3. a formal ecclesiastical curse involving excommunication.
4. any imprecation of divine punishment.
5. a curse; execration.

[Origin: 1520–30; <>]

a·pos·tate /ə pɒsteɪt, -tɪt/

–noun
1. a person who forsakes his religion, cause, party, etc.
–adjective
2. of or characterized by apostasy.

[Origin: 1300–50; ME <>]

hea·then /hiðən/

–noun
1. an unconverted individual of a people that do not acknowledge the God of the Bible; a person who is neither a Jew, Christian, nor Muslim; pagan.
2. an irreligious, uncultured, or uncivilized person.

–adjective
3. of or pertaining to heathens; pagan.
4. irreligious, uncultured, or uncivilized.

[Origin: bef. 900; ME hethen, OE hǣthen, akin to G Heide, heidnisch (adj.), ON heithingi (n.), heithinn (adj.), Goth haithno (n.); perh. akin to heath]

her·e·tic /n. hɛrɪtɪk; adj. hɛrɪtɪk, hərɛtɪk/

–noun
1. a professed believer who maintains religious opinions contrary to those accepted by his or her church or rejects doctrines prescribed by that church.
2. Roman Catholic Church. a baptized Roman Catholic who willfully and persistently rejects any article of faith.
3. anyone who does not conform to an established attitude, doctrine, or principle.
–adjective
4. heretical.

[Origin: 1300–50; ME heretik <>ǐn to choose) + -ikos -ic]

pa·gan /peɪgən/

–noun
1. one of a people or community observing a polytheistic religion, as the ancient Romans and Greeks.
2. a person who is not a Christian, Jew, or Muslim.
3. an irreligious or hedonistic person.
–adjective
4. pertaining to the worship or worshipers of any religion that is neither Christian, Jewish, nor Muslim.
5. of, pertaining to, or characteristic of pagans.
6. irreligious or hedonistic.

[Origin: 1325–75; ME <>]