Where does “merda” come from?

merda (Latin) comes from Proto-Italic (s)merdā, from Proto-Indo-European smerd-h₂- — stench.

merda (Latin): dung, excrement, shit

Definitions

Step	Language	Word	Meaning
1	Proto-Italic	(s)merdā	—
2	Proto-Indo-European	smerd-h₂-	stench

merda — Etymology, Origin & Word History | Etymology Explorer