IPA: //ʌnˈtiːtʃəbl//
KK: /ʌnˈtiːtʃəbl/
Someone or something that cannot be taught or is very difficult to teach.
The student was considered unteachable because he refused to listen to any instructions.
Unteachable → It is formed from "un-" (meaning not) and "teachable" (from the root "teach" which comes from Old English "tǣcan", meaning to show or instruct, combined with the suffix "-able" meaning capable of). The word "unteachable" means not capable of being taught or instructed.
Think of someone who is 'not' ('un-') capable of being 'shown' or 'instructed' ('teachable'). This helps you remember that 'unteachable' refers to someone who cannot be taught.