Where does “underlessor” come from?

underlessor (English) comes from English lessor, from Middle English lessour, from Anglo-Norman lessour, from Old French -our, from Latin -or, from Proto-Italic -ōs, from Proto-Indo-European -ōs, from Proto-Indo-European -oss — Creates action nouns or result nouns from verbs;...

Ancestry of “underlessor”, step by step

underlessor traces back through two separate lines of ancestry.

via English lessor

StepLanguageWordMeaning
1EnglishlessorThe owner of property that is leased
2Middle Englishlessour
3Anglo-Normanlessourlessor
4Old French-ourAlternative form of -or
5Latin-orused to form a third-declension masculine...
6Proto-Italic-ōsCreates masculine action nouns or result nouns...
7Proto-Indo-European-ōsCreates masculine and feminine action nouns or...
8Proto-Indo-European-oss
9Proto-Indo-European-osCreates action nouns or result nouns from verbs;...

via English under

StepLanguageWordMeaning
1EnglishunderIn or at a lower level than; As a subject of;...
2Middle Englishunderunder
3Old Englishunderunder, beneath
4Proto-Germanicunderamong, between; under, beneath; under
5Proto-Indo-Europeanh₁entérbetween
6Proto-Indo-Europeanh₁enin; in, inside

Words derived from “underlessor

Every word from Proto-Indo-European -os