Where does “wināh” come from?

wināh (Pahlavi) comes from Proto-Iranian nas-, from Proto-Indo-European neḱ- — to perish, disappear.

Ancestry of “wināh”, step by step

Step	Language	Word	Meaning
1	Proto-Iranian	nas-	to disappear; to perish
2	Proto-Indo-European	neḱ-	to perish, disappear