'archprophet' originates from Modern English, specifically a compound of the prefix 'arch-' (from Greek 'arkhós' meaning 'chief, principal') and 'prophet' (from Greek 'prophētēs' via Latin 'propheta').

'prophet' entered English via Latin 'propheta' and Anglo-Norman/Old French forms from Greek 'prophētēs'; 'arch-' was borrowed from Greek 'arkhós' and later used productively in English compounds (e.g. 'archbishop', 'archenemy') to mean 'principal' or 'chief', forming the compound 'archprophet' in Modern English.

Initially the components meant 'chief' + 'one who speaks for the gods' and this has directly yielded the modern compound meaning 'chief prophet'.