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 whose abilities are less than normal.
That part of the axis of a curved line which is intercepted between the ordinate and the normal.
denormal
Less than normal.