ἄγρυκτος
From LSJ
εἰ ἀποκρυπτόντων τῶν Μήδων τὸν ἥλιον ὑπὸ σκιῇ ἔσοιτο πρὸς αὐτοὺς ἡ μάχη καὶ οὐκ ἐν ἡλίῳ → if the Medes hid the sun, the battle would be to them in the shade and not in the sun
English (LSJ)
ον, (ἀ- priv., γρύζω)
A not to be spoken of, ἄγρυκτα παθεῖν Pherecr.157. ἀγρυξία, ἡ, dead silence, Pi.Fr.229.
Greek (Liddell-Scott)
ἄγρυκτος: -ον, (α στερητ., γρῦ) ἄρρητος, περὶ οὗ δὲν δύναταί τις νὰ εἴπῃ οὐδὲ γρῦ, ἄγρυκτα παθεῖν, Φερεκρ. Ἄδηλ. 20· - ἐντεῦθεν ἀγρυξία, ἡ· ἄκρα σιγή. Πινδ. Ἀποσπ. 253.
Spanish (DGE)
-ον indecible ἄγρυκτα παθεῖν Pherecr.168.