Inability to read unpleasant article, mostly risqué (10)
I believe the answer is:
illiteracy
'inability to read' is the definition.
(someone illiterate is unable to read)
'unpleasant article mostly risque' is the wordplay.
'unpleasant' becomes 'ill' (feeling ill is feeling unpleasant).
'article' becomes 'item' (both can mean an object or thing).
'mostly' means to remove the last letter.
'risque' becomes 'racy' (synonyms).
'item' with its final letter taken away is 'ite'.
'ill'+'ite'+'racy'='ILLITERACY'
(Other definitions for illiteracy that I've seen before include "ignorance?" , "Inability to read or write" .)