Transcriptions:

Chinese: 可薩 *kʰâ-sât

Chinese: 曷薩 *ɣât-sât

Middle Persian: 𐮀𐮑𐮅𐮊 *x(ä)duːr

Arabic: خَزَر *xäzär

It is tempting to view Xazar as a dynastonym, but it is clearly a tribal name. Moreover, the tribal name is morphologically Oğur despite its Türük-speaking elite. Conceivably, they could have been an Oğur-speaking tribe under the On Oq Bodun; thus, explaining their adoption of the Türük language. Meanwhile, their tamğa, a clear derivative of the Nezäk tamğa, would also have been adopted from the On Oq Bodun, who had already appropriated many of the Xuna's imperial regalia.

If we assume an Oğur origin, Xazar would likely go back to Turkic *kɑ[s]ɑːr with a verbal root *kɑ[s]-. Semantically, the root would probably be related to warfare. We see this in all other identifiable Oğur-type *-ɑːr suffix tribal names. In which case, a derivation from *kɑ[s]- "to constrict, tighten" and thus "oppress" could work. However, its Middle Persian transcription, if accurate, could point to an original *kɑ[d]ɑːr.