There are at least 4 theories floating around to explain how Kazhakstan got its name:
a) It comes from the Turkish verb qaz (to wander), because the Kazakhs were wandering steppemen
b) It derives from the Mongol word khasaq (a wheeled cart used by the Kazakhs to transport their yurts and belongings).
c) The name came from the popular Kazakh legend of the white goose (qaz means "goose", aq means "white"). In this creation myth, a white steppe goose turned into a princess, who in turn gave birth to the first Kazakh.
d) Another theory on the origin of the word Kazakh (originally Qazaq) is that it comes from the ancient Turkic word qazğaq, first mentioned on the 8th century Turkic monument of Uyuk-Turan. According to the notable Turkic linguist Vasily Radlov and the orientalist Veniamin Yudin, the noun qazğaq derives from the same root as the verb qazğan ("to obtain", "to gain"). Therefore, qazğaq defines a type of person who seeks profit and gain.
I have a new theory. My view is, Kazhakstan has a Sanskrit root. Derived from Kashak-stan. Kashak is the sanskrit word for grass. The grassy terrain of the great Kazhak steppe might have been the trigger for Indic nomads to give this name. I shall present more evidence in the coming days.