Where does “smolderingness” come from?

smolderingness (English) comes from English smoldering, from English smouldering, from English -ing, from Old English -ing, from Old English -tūn, from Old English tūn, from Proto-West Germanic tūn, from Proto-Germanic tūną — smoke; mist, haze.

Ancestry of “smolderingness”, step by step

smolderingness traces back through two separate lines of ancestry.

via English smoldering

StepLanguageWordMeaning
1Englishsmolderingpresent participle of smolder; Alternative form...
2Englishsmoulderingpresent participle of smoulder; The act by which...
3English-ingUsed to form gerunds, a type of verbal nouns,...
4Old English-ingForming nouns from verbs, indicating action,...
5Old English-tūnhomestead, village, town
6Old Englishtūnenclosure, yard; place; dwelling
7Proto-West Germanictūnfence
8Proto-Germanictūnąfence; enclosure
9Gaulishdunumfort; hill, hillfort
10Proto-Celticdūnomstronghold, rampart
11Proto-Indo-Europeandʰewh₂-smoke; mist, haze

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 dʰewh₂-Every word from Proto-Celtic dūnomEvery word from English -ing