Where does “тұрақсыз” come from?

тұрақсыз (Kazakh) comes from Kazakh -сіз, from Proto-Turkic siŕ — you; ye.

тұрақсыз (Kazakh): unstable

Definitions

Step	Language	Word	Meaning
1	Kazakh	-сіз	less, de-, non-, un- (suffix used to create adjectives not containing the noun)
2	Proto-Turkic	siŕ	you; ye