In pre-Islamic period it was a name given to guardian spirits who give inspiration to poets. These ''poets'' are people who have status and political power in the society. Poet here probably means a spell caster.
The Latin-derived word
genius (the source of inspiration, creative power, protective spirit) merged with the Arabic
djinn/jinn (جنّ, beings that are hidden or concealed) under the influence of Orientalism in Western culture, becoming the
genie in fairytales that grants wishes (like the stories of Aladdin). We pronounce the
j-n-n root as "c-n-n" in Turkish. Cennet-
Jannah(جَنَّة), meaning heavens, shares the same root. Just as
genius came to mean "a person of exceptional intellect," the
c-n-n root has its own variation in mecnun-
majnun (مَجْنُون), meaning "mad" — yet this madness can be linked to genius. Here, "madness" refers to someone who "thinks with the concealed side," suppressing the rational mind and connecting with the intuitive, feminine, night side of the soul.
The same corruption happened with the word
demon. Initially seen as a divine force or an inspirational being, it was later vilified. Islam did what christianity did to daemon and what Zoroastrianism did to daeva (divine beings later ''demonized'') to concept of djinn.
If a Muslim is dealing with a jinn it is most likely a low level parasitic entity. In pre-islamic period, it was a name for muses and guardian spirits.
For more information, members were talking about this here:
https://ancient-forums.com/threads/gaipten-cinlerin-sesini-duymak.299408/#post-1132299
and here:
https://ancient-forums.com/threads/ruhumuzu-parçalara-bölerek-saklamak.292983/page-2#post-1124325