Where does “arbitrário” come from?

arbitrário (Portuguese) comes from Latin arbitrarius, from Latin -ārius, from Proto-Italic *-āzios.

arbitrário (Portuguese): arbitrary

Definitions

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

arbitrário — Etymology, Origin & Word History | Etymology Explorer