Learned borrowing from Old Turkic 𐰉𐰆𐰑𐰣 (b¹ud¹n¹ /bodun/), plural of 𐰉𐰆𐰑 (b¹ud¹ /bod/). The first vowel was misread as /u/ during the borrowing process.
Practice speaking and memorizing "budun" and many other words and sentences in Turkish.