Where does “ಸುನ್ನ” come from?

ಸುನ್ನ (Old Kannada) comes from Pali sunna, from Sanskrit शून्य, from Proto-Indo-European ḱówH-.

Ancestry of “ಸುನ್ನ”, step by step

Step	Language	Word	Meaning
1	Pali	sunna	—
2	Sanskrit	शून्य	zero; cipher, cypher; blank, deserted
3	Proto-Indo-European	ḱówH-	—

ಸುನ್ನ — Etymology, Origin & Word History | Etymology Explorer