prophetess (n.)

late 12c., "person who speaks for God; one who foretells, inspired preacher," from Old French prophete, profete "prophet, soothsayer" (11c., Modern French prophète) and directly from Latin propheta, from Greek prophētēs (Doric prophatēs) "an interpreter, spokesman, proclaimer; a harbinger" (as cicadas of summer), but especially "one who speaks for a god, inspired preacher or teacher," from pro "before" (from PIE root *per- (1) "forward," hence "in front of, before") + root of phanai "to speak" (from PIE root *bha- (2) "to speak, tell, say").

The Greek word was used in Septuagint for Hebrew nabj "soothsayer, inspired prophet." Early Latin writers translated Greek prophetes with Latin vates, but the Latinized form propheta predominated in post-Classical times, chiefly due to Christian writers, probably because of pagan associations of vates. In English, meaning "prophetic writer of the Old Testament" is from late 14c. Non-religious sense is from 1848; used of Muhammad by 1610s (translating Arabic al-nabiy, and sometimes also al-rasul, properly "the messenger"). The Latin word is glossed in Old English by witga. The Prophets for "the prophetic books of the Old Testament" is by late 14c.

fem. suffix, from French -esse, from Late Latin -issa, from Greek -issa (cognate with Old English fem. agent suffix -icge); rare in classical Greek but more common later, in diakonissa "deaconess" and other Church terms picked up by Latin.