Where does “favoritemost” come from?

favoritemost (English) comes from English favorite, from Middle French favorit, from Old French favorit, from Italian favorito, from Italian favorire, from Italian favore, from Latin favor, from Latin -or — Creates action nouns or result nouns from verbs;...

Ancestry of “favoritemost”, step by step

favoritemost traces back through two separate lines of ancestry.

via English favorite

StepLanguageWordMeaning
1EnglishfavoriteAlternative form of favourite
2Middle Frenchfavoritfavored one
3Old Frenchfavorit
4Italianfavoritofavourite; mollycoddle; teacher's pet
5Italianfavorireto favour, to favor, to help, to aid, to support;...
6Italianfavorefavour
7Latinfavorgood will, inclination, partiality, favor;...
8Latin-orused to form a third-declension masculine...
9Proto-Italic-ōsCreates masculine action nouns or result nouns...
10Proto-Indo-European-ōsCreates masculine and feminine action nouns or...
11Proto-Indo-European-oss
12Proto-Indo-European-osCreates action nouns or result nouns from verbs;...

via English most

StepLanguageWordMeaning
1Englishmostsuperlative degree of much; superlative degree of...
2Middle Englishmost
3Old Englishmǣstmost
4Proto-Germanicmaistazsuperlative degree of *mikilaz; most
5Proto-Germanicmikilazgreat, large; much, many
6Proto-Indo-Europeanmeǵa-
Every word from Proto-Indo-European -os