Where does “insubstantiated” come from?

insubstantiated (English) comes from English in, from Middle English in, from Old English in, from Proto-West Germanic *in.

Ancestry of “insubstantiated”, step by step

insubstantiated traces back through two separate lines of ancestry.

via English in

StepLanguageWordMeaning
1EnglishinUsed to indicate location, inclusion, or position...
2Middle EnglishinAny kind of accomodation; particularly; A home or...
3Old Englishinin; Alternative form of inn
4Proto-West Germanic*in

via English substantiated

StepLanguageWordMeaning
1Englishsubstantiatedsimple past tense and past participle of...
Every word from Proto-West Germanic *inEvery word from Old English inEvery word from Middle English in
insubstantiated — Etymology, Origin & Word History | Etymology Explorer