Where does “arbitrario” come from?

arbitrario (Spanish) comes from Latin arbitrarius, from Latin -ārius, from Proto-Italic *-āzios.

arbitrario (Spanish): arbitrary

Definitions

Step	Language	Word	Meaning
1	Latin	arbitrarius	arbitrating; arbitrary
2	Latin	-ārius	—
3	Proto-Italic	*-āzios	—

arbitrario — Etymology, Origin & Word History | Etymology Explorer