Incapable
/ɪnˈkeɪpəbl̩/
noun
One who is morally or mentally weak or inefficient; an imbecile; a simpleton.
adjective
Not capable (of doing something); unable.
“A pint glass is incapable of holding more than a pint of liquid.”
Not in a state to receive; not receptive; not susceptible; not able to admit.
“incapable of pain, or pleasure; incapable of stain or injury”