Where does “насущный” come from?

насущный (Russian) comes from Old Church Slavonic насѫщьнъ, from Old Church Slavonic на, from Proto-Slavic na, from Proto-Indo-European h₂en- — on, onto.

насущный (Russian): vital, essential, urgent, necessary

Definitions

vital, essential, urgent, necessary

Ancestry of “насущный”, step by step

Step	Language	Word	Meaning
1	Old Church Slavonic	насѫщьнъ	vital, essential, urgent, necessary, supersubstantial
2	Old Church Slavonic	на	onto, on; into, in
3	Proto-Slavic	na	on; concerning; onto
4	Proto-Indo-European	h₂en-	on, onto

Every word from Proto-Indo-European h₂en- →Every word from Proto-Slavic na →Every word from Old Church Slavonic на →