Where does “sontuosissimo” come from?

sontuosissimo (Italian) comes from Italian sontuoso, from Latin sumptuōsus, from Latin sūmptus, from Latin sumō, from Latin sub-, from Proto-Indo-European upó, from Proto-Indo-European h₃ewp-.

Ancestry of “sontuosissimo”, step by step

Step	Language	Word	Meaning
1	Italian	sontuoso	sumptuous
2	Latin	sumptuōsus	Very expensive or costly
3	Latin	sūmptus	assumed, claimed
4	Latin	sumō	to take, take up, catch, assume, seize, claim, arrogate
5	Latin	sub-	under, sub
6	Proto-Indo-European	upó	under, below
7	Proto-Indo-European	h₃ewp-	—

Every word from Proto-Indo-European h₃ewp- →Every word from Proto-Indo-European upó →Every word from Latin sub- →