Where does “unthinkingly” come from?

I notice the etymology chain provided appears problematic—it traces "unthinking" back through "thinking" and "think" to Latin "unus" (meaning "one"), which doesn't establish a coherent semantic or phonetic relationship for the word "unthinkingly." Could you verify the chain? A typical etymology for "unthinkingly" would trace: - English unthinkingly ← English unthinking (un- + thinking) ← English think ← Old English thencan/þencan The current chain seems to conflate two unrelated etymologies. I'm happy to write the one-sentence summary once the chain is clarified.

unthinkingly (English): In an unthinking manner

Definitions

  1. In an unthinking manner

Ancestry of “unthinkingly”, step by step

StepLanguageWordMeaning
1EnglishunthinkingWithout proper thought; thoughtless; Showing no...
2EnglishUn-not
3EnglishstillNot moving; calm; Not effervescing; not...
4Old Englishstillanbecome calm, abate, subside; calm, pacify,...
5Proto-West Germanicstillijanto make still, quiet
6Proto-West Germanic-janCreates denominative verbs from nouns; Creates...
7Proto-Germanic-janąDerives denominatives from nouns and factitives...
8Proto-Indo-European-yétiCreates intransitive, often deponent,...
9Proto-Indo-Europeanyé-
10Chichewaiyehe, she
Every word from Chichewa iyeEvery word from Proto-Germanic -janąEvery word from English Un-