Where does “*ɸroboudom” come from?

*ɸroboudom (Proto-Celtic) comes from Proto-Indo-European bʰewdʰ- — to be awake, be aware.

Ancestry of “*ɸroboudom”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	bʰewdʰ-	to be awake, be aware