Where does “ἀδιάφορος” come from?

ἀδιάφορος (Ancient Greek) comes from Ancient Greek διάφορος, from Ancient Greek διαφέρω, from Ancient Greek φέρω, from Proto-Hellenic pʰérō, from Proto-Indo-European bʰéreti, from Proto-Indo-European bʰēr- — shiny, light brown.

ἀδιάφορος (Ancient Greek): indifferent