Where does “-phobus” come from?

-phobus (Latin) comes from Ancient Greek Φόβος, from Proto-Indo-European bʰegʷ- — to flee; to run.

Ancestry of “-phobus”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Φόβος	mythological personification of fear
2	Proto-Indo-European	bʰegʷ-	to flee; to run

-phobus — Etymology, Origin & Word History | Etymology Explorer