Where does “фәлән” come from?

фәлән (Bashkir) comes from Arabic فُلَان — so-and-so.

фәлән (Bashkir): such-and-such, so-and-so

Definitions

Step	Language	Word	Meaning
1	Arabic	فُلَان	so-and-so

фәлән — Etymology, Origin & Word History | Etymology Explorer