idolatry (n.)

mid-13c., "image of a deity as an object of (pagan) worship," from Old French idole "idol, graven image, pagan god" (11c.), from Latin idolum "image (mental or physical), form," especially "apparition, ghost," but used in Church Latin for "false god, image of a pagan deity as an object of worship." This is from Greek eidōlon "mental image, apparition, phantom," also "material image, statue," in Ecclesiastical Greek," a pagan idol," from eidos "form, shape; likeness, resemblance" (see -oid).

A Greek word for "image," used in Jewish and early Christian writers for "image of a false god," hence also "false god." The Germanic languages generally began with a word for "god" prefixed to indicate "false god" (literally "off-god"), hence "image of a false god" (Old English afgod, Danish afgud, Swedish avgud, Old High German abgot, compounds with af-/ab- "away, away from" (source of off) + god). Old Norse skurgoð "idol" is literally "carved god."

The older Greek senses sometimes have been used in English. The figurative sense of "something idolized" is by 1560s (in Middle English the figurative sense was "someone who is false or untrustworthy"). The meaning "a person regarded with the reverence due a deity, human object of adoring devotion" is from 1590s.

"concern for the letter (of Scripture) without regard for the spirit," 1847 (German Grammatolatrie is attested by 1842), from Latinized form of Greek grammatik-, combining form of gramma "letter" (see -gram) + -latry "worship of." Probably formed with allusion to idolatry.