This is the 12980th most frequent Turkish word.
kalmayacağın
"(Something) that you will not stay."
'Kalmayacağın' indicates a future negative action, that you will not stay.
Bu gece burada kalmayacağın için hazırlık yapmıyoruz.
Since you will not stay here tonight, we are not preparing.
'Kalmayacağın' is used as part of a conditional statement to denote not staying.
Eğer toplantıya kalmayacağın kesin ise, erkenden çıkabiliriz.
If it is certain that you will not stay for the meeting, we can leave early.
Here, 'kalmayacağın' introduces a clause explaining the future action of not staying.