Where does “Geirtrúð” come from?

Geirtrúð (Faroese) comes from Old Norse Geirþrúðr, from Old Norse geirr, from Proto-Germanic gaizaz, from Proto-Indo-European ǵʰoysós, from Proto-Indo-European ǵʰey- — winter.

Ancestry of “Geirtrúð”, step by step

Step	Language	Word	Meaning
1	Old Norse	Geirþrúðr	—
2	Old Norse	geirr	spear
3	Proto-Germanic	gaizaz	spear, pike, javelin
4	Proto-Indo-European	ǵʰoysós	throwing spear
5	Proto-Indo-European	ǵʰey-	winter

Every word from Proto-Indo-European ǵʰey- →Every word from Proto-Indo-European ǵʰoysós →Every word from Proto-Germanic gaizaz →