Where does “vastāre” come from?

vastāre (Latin) comes from Proto-Indo-European weh₂st- — empty, wasted; empty; wasted.

Ancestry of “vastāre”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	weh₂st-	empty, wasted; empty; wasted

vastāre — Etymology, Origin & Word History | Etymology Explorer