From Wiktionary, the free dictionary
From super- + ancient.
superancient (comparative more superancient, superlative most superancient)
- (rare) Exceedingly ancient.
2003, M. G. Harris, The Joshua Files: Zero Moment[1], Walker, →ISBN, page 28:Those four books contain the inscriptions that Itzamna found in a superancient ruin near the Mayan city of Izapa.
2016, Robert Ellwood, Harry Partin, Religious and Spiritual Groups in Modern America[2], Taylor & Francis, →ISBN, page 28:He mentioned an arcane superancient scripture preserved in central Asia.
2017, Matthew Reilly, The Four Legendary Kingdoms[3], Gallery Books, →ISBN, page 132:"My postulation," Mae said, "is that our gods of old---from Zeus to Poseidon, to Anubis and Isis---were all royal benificiaries of the superancient civilization that built the Machine.