Exonym
J. Harmatta considers Old Persian "Kambaujiya- as an apotropaic name meaning "weak", to Avestan Kambishta-, "the least" a name which, he says, was given to the Kambojas by their enemies. The same scholar adds that the name is a remainder of an archaic name giving habit. This is shown by the alleged disappearance of the name after the death of Cambyses (Kambaujiya) in 522 BC. Unfortunately for Harmatta, the name still occurred in the three Elamite tablets dated 498-497 and 501-500 BCE ". Prof Wojciech Skalmowski rejected Harmatta's etymology on the basis that Herodotus attests that "their (i.e the Persians) names agree with the nature of their persons and their nobility".
Prof Wojciech Skalmowski who rejected Harmatta's etymology of Kambaujiya has suggested that the name Kambaujiya ( and Kamboja) is an adjectival form from a compound like *kamp + auj-ias- (cf. Sanskrit kampate " = he trembles", Avestan *auj, as in aojvah, "stronger than"), meaning "unshaken, stronger than trembling, undaunted, intrepid (intrepidus)". Therefore, this would give the name Kamboja a meaning like powerful, mighty, fearful, undaunted, valiant etc.
Read more about this topic: Kamboja (name)