Where does “vackel” come from?

vackel (Old High German) comes from Latin facula, from Latin fax, from Proto-Indo-European ǵʷʰeh₂k- — to shine.

Ancestry of “vackel”, step by step

Step	Language	Word	Meaning
1	Latin	facula	small torch
2	Latin	fax	torch, firebrand; fireball, comet; cause of ruin,...
3	Proto-Indo-European	ǵʷʰeh₂k-	to shine

vackel — Etymology, Origin & Word History | Etymology Explorer