The main difference between the two is that "yok" is generally used to describe absense. Evde süt yok./ Masada kalem yok. It is also used when we say we don't have/ own something: Benim küçük kardeşim yok, ablam var. "Yok" can also be used in a completely different manner, and in those cases it simply means "no".In every day speech "yok" and "hayır" are used indifferently. As a native speaker, I would answer this question with with either hayır or yok: Eve gidecek misin? -Hayır/Yok gitmeyeceğim. Both words serve the same purpose, but generally "yok" has a more milder/nicer connotation. "Hayır" sounds more strict and rude at times, while when someone says "yok" it sounds like what you are asking for is not possible at that moment. Here are some other examples: You go to a restaurant and ask if you can use their washroom- Lavabonuzu kullanabilir miyim? Hayır, kullanmazsınız. Lavabomuz sadece müşteriler içindir. (NO! The bathroom is only for customers) Yok, şimdi kullanmazsınız çünkü dolu. (No, you cannot use it because it is occupied.) You ask your friend if you could borrow his car. Arabanı ödünç alabilir miyim? Hayır alamazsın (No way!) Yok alamazsın ( You can't)--- he is being nice. You are at a friends house and her family comes over. You ask if you should leave: Kalayım mı? Hayır git (No, just go)-- sounds rude Yok git (I think you should just leave)-- sounds nicer.

Hi Milfezer , I can say that there is no many difference between yok and hayir . Hayir's meaning is No . Yok's meanings are absent , not , nope , nothing and something like that