UNTEACHABLE
a.That cannot be taught or instructed; indocile.
UNTEACHABLENESS
n.The quality of not readily receiving instruction; indocility.
unteachable
un teach a ble |ˌənˈtēCHəbəl ˌənˈtitʃəbəl | ▶adjective (of a student or skill ) unable to be taught.
un |teach ¦able |ʌnˈtiːtʃəb (ə )l | ▶adjective (of a pupil or skill ) unable to be taught.