Where does “insulsissimo” come from?

insulsissimo (Italian) comes from Italian insulso, from Latin insulsus, from Latin īn-, from Latin în, from Latin en, from Proto-Italic en, from Proto-Indo-European h₁én — in.

Ancestry of “insulsissimo”, step by step

Step	Language	Word	Meaning
1	Italian	insulso	dull, silly, foolish, insipid, namby-pamby
2	Latin	insulsus	unsalted, flavorless; bungling, awkward; insipid,...
3	Latin	īn-	un-, non-, not
4	Latin	în	in, at, on, upon, from (space)
5	Latin	en	lookǃ beholdǃ; reallyǃ?; come onǃ
6	Proto-Italic	en	in
7	Proto-Indo-European	h₁én	in

Every word from Proto-Indo-European h₁én →Every word from Latin īn- →Every word from Proto-Italic en →