The story
- Proto-Indo-European*h₂ent-
- Proto-Indo-European*h₂énts
- Proto-Indo-European*h₂énti
- Ancient Greekᾰ̓ντῐ́ (ăntĭ́)
- Ancient Greekἀντι- (anti-)
- Englishanti-
- Englishvenom
- English todayantivenom
From anti- + venom, q.v. Piecewise doublet of antivenene and antivenin.
Etymology from Wiktionary, CC BY-SA 4.0.