Where does “molestieren” come from?

molestieren (German) comes from Latin molestus, from Latin mōlēs — multitude, mass (of material).

Ancestry of “molestieren”, step by step

Step	Language	Word	Meaning
1	Latin	molestus	troublesome, irksome, grievous, annoying,...
2	Latin	mōlēs	multitude, mass (of material)