godan verb (-su), transitive verb
Transitive verb: to soak something in liquid until it softens or swells. Often used for dried foods like beans or seaweed, or for softening something in water.
豆を一晩水にふやかす。
Soak the beans in water overnight.
乾燥わかめを水
Rehydrate dried wakame in water before using it in cooking.