"İnsan" is basically person (as human) "Kişi" is also person but non-specific, individual. (You can use "kişi" as "person" in English but in Turkish, it might seem wrong, in some usages. Like, "Kaç insanlardı?" is wrong but "Kaç kişilerdi?" is right. But you can also say it like "Kaç insan vardı?". So "kişi" is a usage of "insan" but like I said, it's non-specific.) -Yarın kaç kişi gelecek? ✓ -Orada sadece 3 kişiydik. ✓ -Konuşmakta zorluk yaşayan kişiler/insanlar... ✓ -Bazı kişiler/insanlar ✓ by the way "kişilik" means "personality" , you can see the similarity. "Adam" is simply "man". Could be used as "guy" or "person" but you can never call a woman "adam". In daily speak of Turkish, "adam" is used for good man. There is an expression like "Adam gibi adam" which means the guy is awesome haha. (has good personality)

İnsan انسان Kişi شخص Adam بني ادم ههه