Where does “bismer” come from?

bismer (Middle Low German) comes from Old East Slavic безмѣнъ, from Arabic وَزْنَة, from Arabic وَزْن — weight.

Ancestry of “bismer”, step by step

Step	Language	Word	Meaning
1	Old East Slavic	безмѣнъ	—
2	Arabic	وَزْنَة	—
3	Arabic	وَزْن	weight