Where does “mníȟaȟa” come from?

mníȟaȟa (Dakota) comes from Dakota mní, from Proto-Siouan *wa-rį́· — water, liquid.

Ancestry of “mníȟaȟa”, step by step

Step	Language	Word	Meaning
1	Dakota	mní	water
2	Proto-Siouan	*wa-rį́·	water, liquid