Seven points written after one shows incompetence (9)
I believe the answer is:
ineptness
'incompetence' is the definition.
(ineptness is a kind of incompetence)
'seven points written after one' is the wordplay.
I cannot quite see how this works, but
'points' could be 'nes' (NE is an example) and 'nes' is found within the answer.
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'shows' acts as a link.
Can you help me to learn more?
(Other definitions for ineptness that I've seen before include "Clumsiness, lack of skill" , "Lack of suitability" , "Awkwardness, clumsiness" .)