Where does “bitu” come from?

bitu (Proto-Celtic) comes from Proto-Indo-European bʰeyh₂- — to fear, be afraid; to strike, hit; to hew, cut.

Ancestry of “bitu”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	bʰeyh₂-	to fear, be afraid; to strike, hit; to hew, cut

bitu — Etymology, Origin & Word History | Etymology Explorer