| OPI | obstinate in your opinions |
|---|---|
| OPI | gastropods having the gills when present posterior to the heart and having no operculum: includes sea slugs |
| OPI | comprising the hoatzins |
| OPI | type genus of the Opisthocomidae: hoatzins |
| OPI | crested ill-smelling South American bird whose young have claws on the first and second digits of the wings |
| OPI | jawfishes |
| OPI | having receding jaws |
| OPI | infestation with flukes obtained from eating raw fish |
| OPI | severe spasm in which the back arches and the head bends back and heels flex toward the back |
| OPI | an addictive narcotic extracted from seed capsules of the opium poppy |
| OPI | someone addicted to opium |
| OPI | a building where opium is sold and used |