Where does “bič” come from?

bič (Old Czech) comes from Proto-Slavic bičь, from Proto-Indo-European bʰiH-ti̯o.

Ancestry of “bič”, step by step

Step	Language	Word	Meaning
1	Proto-Slavic	bičь	whip
2	Proto-Indo-European	bʰiH-ti̯o	—

bič — Etymology, Origin & Word History | Etymology Explorer