The word’s suggested etymology (see DMLBS) is Ancient Greek: οπος (‘juice’) and πυρ (‘fire’). The context of A-N Med i 179 indicates that the preparation was probably an opiate.
s.
1med.pharm.medicinal preparation or opiate that induces a fiery sensation:
(
s.xiii2/4; MS: s.xiii3/4
)
Et quant vus l’averes purgé, si li dongne l’en auream ou opopire ou autres chaudes opiates
i 179
(
c.1300; MS: s.xivin
)
Ausi donet checune nuyt opopiram ou esdram ou auream alexandrinam ou tiriake ou mitridatum, mes seit destempré ovekes eawe de la decoction de sauge e castoreum
ii 148.62
opopire (s.xiii2/4)