I.not seen or known, unknown, obscure, Hes., Soph., Plat.
II.of things, ἄδ. θάνατοι death by an unknown hand, Soph.; ἄδ. ἔχθρα secret enmity, Thuc.; ῥεῖ πᾶν ἄδηλον melts all to nothing, Soph.; ἄδ. τινι unseen, unobserved by him, Xen.
b.neut. ἄδηλόν [ἐστι] εἰ . . , ὅτι . . , it is uncertain whether . . , unknown that . . , Plat., etc.; so, ἄδηλον μή . . , id=Plat.:— absol., ἄδηλον ὄν it being uncertain, Thuc.; so, ἐν ἀδηλοτέρῳ εἶναι Xen.