Mid 17th century; earliest use found in Thomas Randolph (d. 1635), poet and playwright. From post-classical Latin acroamaticus privately communicated by oral teaching to chosen disciples only, esoteric, secret, disposed to listen and its etymon Hellenistic Greek ἀκροαματικός designed for hearing only, delivered orally, esoteric, capable of listening from ancient Greek ἀκροαματ-, ἀκρόαμα + -ικός. Compare Middle French, French †acroamatique, French acromatique.