unteachable
adjective uk/ˌʌnˈtiː.tʃ.ə.bəl/ us/ˌʌnˈtiː.tʃ.ə.bəl/
（技能等）不适合教的，无法传授的;（人）不可教的，冥顽的
A person or a subject or skill that is unteachable cannot be taught.
The dyslexic author had once been considered "unteachable" at school. 这位有阅读障碍的作者曾经在学校被认为是“不可教”的。
Good salesmen have the unteachable quality of enthusiasm. 优秀的推销员都有一种与生俱来、无法传授予他人的热情。