From the word "dehydrated".
1. The refreshing feeling when one has consumed large amounts of water after a straining exercise or during an extremely hot day. Generally curing dehydration.
2. Also useable as a verb: to rehydrate.
Ex 1: In the euphoria that followed my rehydration I fell asleep naked on the floor.
Ex 2: Had I not rehydrated, I would surely have evaporated in the heat.