Where does “ἱερατικός” come from?

ἱερατικός (Ancient Greek) comes from Ancient Greek ἱερατεία, from Ancient Greek ἱερατεύω, from Ancient Greek ἱερεύς, from Ancient Greek ἱερός, from Proto-Hellenic iherós, from Proto-Indo-European ish₁ros.

ἱερατικός (Ancient Greek): of or for the priest's office, priestly