Where does “sn̥gʷ-” come from?

sn̥gʷ- (Proto-Indo-European) comes from Proto-Indo-European sengʷ- — to sink; to fall; to drop.

Ancestry of “sn̥gʷ-”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	sengʷ-	to sink; to fall; to drop

sn̥gʷ- — Etymology, Origin & Word History | Etymology Explorer