Where does “smȏrdъ” come from?

smȏrdъ (Proto-Slavic) comes from Proto-Balto-Slavic smorʔdos, from Proto-Indo-European smord-o-s.

Ancestry of “smȏrdъ”, step by step

Step	Language	Word	Meaning
1	Proto-Balto-Slavic	smorʔdos	—
2	Proto-Indo-European	smord-o-s	—

smȏrdъ — Etymology, Origin & Word History | Etymology Explorer