ἀθεμείλιος
From LSJ
αἱ μέν ἀποφάσεις ἐπί τῶν θείων ἀληθεῖς, αἱ δέ καταφάσεις ἀνάρμοστοι τῇ κρυφιότητι τῶν ἀποῤῥήτων → as concerns the things of the gods, negative pronouncements are true, but positive ones are inadequate to their hidden character
English (LSJ)
ον, without foundation, Ep. word implied by Hsch. ἀθέμηλος· οὐδὸν οὐκ ἔχουσα οὐδὲ θεμέλιον, and ἀθεμίλιος· ἀκροσφαλής, ψεύστης.