Where does “книжища” come from?

книжища (Russian) comes from Russian кни́га, from Proto-Slavic kъňiga, from Old High German kenning — symbol, sign.

Ancestry of “книжища”, step by step

StepLanguageWordMeaning
1Russianкни́гаbook
2Proto-Slavickъňigabook
3Old High Germankenningsymbol, sign
Every word from Old High German kenning →Every word from Proto-Slavic kъňiga →Every word from Russian кни́га →