Where does “skatho” come from?

skatho (Old Dutch) comes from Proto-West Germanic *skaþō, from Proto-Germanic skaþô, from Proto-Indo-European sket- — to injure.

Ancestry of “skatho”, step by step

Step	Language	Word	Meaning
1	Proto-West Germanic	*skaþō	—
2	Proto-Germanic	skaþô	damage, scathe; one who causes damage; injurer
3	Proto-Indo-European	sket-	to injure

skatho — Etymology, Origin & Word History | Etymology Explorer