Where does “vanvit” come from?

vanvit (Old Norse) comes from Old Norse vit, from Proto-Germanic wit, from Proto-Germanic *wet, from Proto-Indo-European wéy, from Proto-Indo-European éǵh₂ — I.

Ancestry of “vanvit”, step by step

Step	Language	Word	Meaning
1	Old Norse	vit	first-person dual pronoun
2	Proto-Germanic	wit	Alternative form of *wet
3	Proto-Germanic	*wet	—
4	Proto-Indo-European	wéy	we
5	Proto-Indo-European	éǵh₂	I

Words derived from “vanvit”

vanvid
vanvett
vanvetting

Every word from Proto-Indo-European éǵh₂ →Every word from Proto-Indo-European wéy →Every word from Proto-Germanic *wet →