Where does “mélyōs” come from?

mélyōs (Proto-Indo-European) comes from Proto-Indo-European mel-, from Proto-Indo-European mey- — to strengthen; to bind; to change, exchange.

Ancestry of “mélyōs”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	mel-	soft; tender; weak; to deceive; to rub
2	Proto-Indo-European	mey-	to strengthen; to bind; to change, exchange

mélyōs — Etymology, Origin & Word History | Etymology Explorer