1. A reference to an abnormal fear of rain or of being rained on: Susan had a pluvialphobous reaction when she saw that it was drizzling outside and so she decided not to go out at all, dreading to get wet.
2. Pertaining to herbs and other living species that cannot survive with excessive rains: Robert loved his cacti and since he knew them to be pluvialphbous plants, he didn’t water them very often.