Where does “mundānus” come from?

mundānus (Latin) comes from Latin mundus, from Proto-Indo-European mewH- — to wash, wet; to make wet, wash; wet.

Ancestry of “mundānus”, step by step

Step	Language	Word	Meaning
1	Latin	mundus	clean, pure; neat; nice, fine, elegant,...
2	Proto-Indo-European	mewH-	to wash, wet; to make wet, wash; wet