Where does “vilkaus” come from?

vilkaus (Finnish) comes from Finnish vilkaista, from Finnish vilkkua, from Proto-Finnic vilkkudak.

Ancestry of “vilkaus”, step by step

Step	Language	Word	Meaning
1	Finnish	vilkaista	To glance, take a look, have a look; take a look...
2	Finnish	vilkkua	to flash, to blink, to flicker; to twinkle;...
3	Proto-Finnic	vilkkudak	—