δυσαποδίδακτος
From LSJ
Ὁ θάνατος οὐθὲν πρὸς ἡμᾶς, ἐπειδήπερ ὅταν μὲν ἡμεῖς ὦμεν, ὁ θάνατος οὐ πάρεστιν, ὅταν δὲ ὁ θάνατος παρῇ, τόθ' ἡμεῖς οὐκ ἐσμέν. → Death is nothing to us, since when we are, death has not come, and when death has come, we are not.
English (LSJ)
[ῐ], ον,
A hard to unlearn, J.AJ16.2.4.