incompetent

Etymology

From French incompétent, from Late Latin incompetentem, from Latin incompetēns.

adj

1. Unskilled; lacking the degree of ability and responsibility that would normally be expected.
   Having an incompetent lawyer may be grounds for a retrial, but the lawyer in question probably doesn't know that.
2. Unable to make rational decisions; insane or otherwise cognitively impaired.
   The charged was judged incompetent to stand trial, at least until his medication started working.
3. (medicine, of the cervix) Opening too early during pregnancy, resulting in miscarriage or premature birth.
4. (geology) Not resistant to deformation or flow.

noun

1. A person who is incompetent.