Where does “unperishableness” come from?

unperishableness (English) comes from English unperishable, from English perishable, from English perish, from Middle English perishen, from Old French perir, from Latin pereō, from Latin eō, from Proto-Italic eō — to go.

Ancestry of “unperishableness”, step by step

unperishableness traces back through two separate lines of ancestry.

via English unperishable

StepLanguageWordMeaning
1EnglishunperishableNot perishable
2EnglishperishableThat which perishes or is short-lived; food that...
3EnglishperishTo decay and disappear; to waste away to nothing;...
4Middle Englishperishen
5Old Frenchperirto die; to perish
6Latinpereōto perish, pass away, die, be ruined
7Latinto go, to fare, to move (oneself) (any kind of animate or inanimate motion: walk, ride, sail, fly, etc.)
8Proto-ItalicI go
9Proto-Italicejō
10Proto-Indo-Europeanh₁éytito go, to be going
11Proto-Indo-Europeanh₁ey-to go

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 h₁ey-