Where does “стыдно” come from?

стыдно (Russian) comes from Russian сты́дный, from Russian -ный, from Old Church Slavonic -ьнъ, from Proto-Slavic -ьnъ — -ish, -ic, -al, -ed; From adjectives.

Ancestry of “стыдно”, step by step

StepLanguageWordMeaning
1Russianсты́дныйshameful
2Russian-ный-ish, -ic, -al, -ed
3Old Church Slavonic-ьнъish, -ic, -al, -ed
4Proto-Slavic-ьnъ-ish, -ic, -al, -ed; From adjectives
Every word from Proto-Slavic -ьnъ →Every word from Russian -ный →Every word from Old Church Slavonic -ьнъ →