Where does “unexplicableness” come from?

unexplicableness (English) comes from English unexplicable, from English inexplicable, from Middle English inexplicable, from Middle French inexplicable, from Latin inexplicabilis, from Latin explicabilis, from Latin -bilis, from Proto-Italic -ðlis — Alternative form of *-trom; instrumental suffix;...

Ancestry of “unexplicableness”, step by step

unexplicableness traces back through two separate lines of ancestry.

via English unexplicable

StepLanguageWordMeaning
1Englishunexplicable
2EnglishinexplicableImpossible to explain; not easily accounted for
3Middle Englishinexplicable
4Middle Frenchinexplicable
5Latininexplicabilisinexplicable
6Latinexplicabilisthat may be explained, explicable, explainable
7Latin-bilis-ble
8Proto-Italic-ðlisForms adjectives from verb stems indicating capacity or worth of being acted on
9Proto-Indo-European-dʰlis
10Proto-Indo-European-dʰlomAlternative form of *-trom; instrumental suffix;...

via English Ness

StepLanguageWordMeaning
1EnglishNessAn Ulster princess and the mother of Conchobar mac Nessa and Findchoem in the Ulster Cycle of Irish mythology. Daughter of Eochaid Sálbuide. Also the mother of Cormac Cond Longas by incest with Conchobar mac Nessa
2Middle Englishnesse
3Old Englishnæsnot, not at all; not; first/third-person singular...
4Proto-Germanicnasjąfoothill; headland; cape
5Proto-Indo-Europeannéh₂snose
Every word from Proto-Indo-European -dʰlomEvery word from Latin -bilisEvery word from Latin explicabilis