I want to know the answer to the following question:
Why is it hard to find the origin of the word Tajik?
All the background I'm provided with is that "The suffix "-stan" (Persian: ـستان‎‎ -stān) is Persian for "place of" or "country" and Tajik is, most likely, the name of a pre-Islamic (before the seventh century A.D.) tribe.". Is that enough to answer the question?