Where does “kovistella” come from?

kovistella (Finnish) comes from Finnish kovistaa, from Finnish kova, from Proto-Finnic kova — hard.

kovistella (Finnish): To bully

Definitions

Step	Language	Word	Meaning
1	Finnish	kovistaa	to come down harshly on someone for some reason;...
2	Finnish	kova	hard; strict, harsh, severe, unfriendly, hard,...
3	Proto-Finnic	kova	hard

kovistella — Etymology, Origin & Word History | Etymology Explorer