A person who is incompetent.
Not resistant to deformation or flow.
Unable to make rational decisions; insane or otherwise cognitively impaired.
Opening too early during pregnancy, resulting in miscarriage or premature birth.
Unskilled; lacking the degree of ability that would normally be expected.
A person or work that does not exhibit originality.
Not being the first or earliest version of something, not original.
Lacking originality.