incapable

adjective

1. (followed by ‘of’) lacking capacity or ability"incapable of carrying a tune"
2. not being susceptible to or admitting of something (usually followed by ‘of’)"incapable of solution"
3. (followed by ‘of’) not having the temperament or inclination for"simply incapable of lying"
4. not meeting requirements"unequal to the demands put upon him"