before vowels ophi-, word-forming element meaning "a snake, serpent," from Greek ophio-, combining form of ophis "serpent, a snake," probably from PIE *egwhi- (source also of Sanskrit ahi-, Avestan aži- "snake," and perhaps the first element of a Germanic word for "lizard," i.e. Old High German egi-dehsa). Hence ophiolatry "serpent-worship" (1862), and the 2c. sect of the Ophitæ, who revered the serpent as the symbol of divine wisdom.
word-forming element of Greek origin meaning "divination by means of," from Old French -mancie, from Late Latin -mantia, from Greek manteia "oracle, divination," from mantis "one who divines, a seer, prophet; one touched by divine madness," from mainesthai "be inspired," which is related to menos "passion, spirit" (from PIE *mnyo-, suffixed form of root *men- (1) "to think," with derivatives referring to qualities and states of mind or thought). Compare mania.
<a href="https://www.etymonline.com/word/ophiomancy">Etymology of ophiomancy by etymonline</a>
Harper, D. (n.d.). Etymology of ophiomancy. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/ophiomancy