Where does “sabio” come from?

sabio (Old Spanish) comes from Latin sapĭdus, from Latin -idus, from Proto-Italic *-iðos.

Ancestry of “sabio”, step by step

Step	Language	Word	Meaning
1	Latin	sapĭdus	—
2	Latin	-idus	tending to
3	Proto-Italic	*-iðos	—