What is a person possessed by a Jinn (manfoos)? And is there a cure for them?

The term "al-manfoos" (المنفوس) has several meanings: humankind in general, a newborn, a precious and desirable item, and one afflicted by the evil eye or envy. If the intended meaning is someone afflicted by the evil eye, the treatment is either by identifying the person who cast the evil eye (al-ʿāʾin) and instructing them to perform ghusl (ritual bath) or wudu (ablution), then the patient is given some of this water to drink; or by washing something that belonged to the person who cast the evil eye and pouring that water over the patient. If the person who cast the evil eye is unknown, the treatment involves ruqya (incantations) and legitimate adhkar (remembrances of Allah).