incompetent

adjective

1
not meeting requirements
unequal to the demands put upon him
2
not qualified or suited for a purpose
an incompetent secret service
the filming was hopeless incompetent
3
legally not qualified or sufficient
a wife is usually considered unqualified to testify against her husband
incompetent witnesses
4
not doing a good job
incompetent at chess
5
showing lack of skill or aptitude
a bungling workman
did a clumsy job

Also useful for “incompetent”:Crossword— A long fill for tough grids