Where does “gwyt” come from?

gwyt (Middle Welsh) comes from Latin vitium, from Proto-Indo-European wi-tio-, from Proto-Indo-European wei — guilt, vice, fault.

Ancestry of “gwyt”, step by step

Step	Language	Word	Meaning
1	Latin	vitium	flaw, defect, blemish, error, fault; vice; crime
2	Proto-Indo-European	wi-tio-	—
3	Proto-Indo-European	wei	guilt, vice, fault