Where does “rigorosissimo” come from?

rigorosissimo (Italian) comes from Italian rigoroso, from Latin rigorosus, from Latin rigor, from Latin -or, from Proto-Italic -ōs, from Proto-Indo-European -ōs, from Proto-Indo-European -oss, from Proto-Indo-European -os — Creates action nouns or result nouns from verbs;...

Ancestry of “rigorosissimo”, step by step

StepLanguageWordMeaning
1Italianrigorosostrict, rigorous, severe; rigorous, exact,...
2Latinrigorosusstiff, rigid; inflexible; rigorous
3Latinrigorstiffness, rigidity; rigor, cold, harshness,...
4Latin-orused to form a third-declension masculine...
5Proto-Italic-ōsCreates masculine action nouns or result nouns...
6Proto-Indo-European-ōsCreates masculine and feminine action nouns or...
7Proto-Indo-European-oss
8Proto-Indo-European-osCreates action nouns or result nouns from verbs;...
Every word from Proto-Indo-European -osEvery word from Latin -orEvery word from Latin rigor