Where does “smrad” come from?

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

Ancestry of “smrad”, step by step

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

smrad — Etymology, Origin & Word History | Etymology Explorer