I will repeat, unable to read (10)
I believe the answer is:
illiterate
'unable to read' is the definition.
(I've seen this in another clue)
'i will repeat' is the wordplay.
'i will' becomes 'I'll' (abbreviation).
'repeat' becomes 'iterate' (synonyms).
'ill'+'iterate'='ILLITERATE'
(Other definitions for illiterate that I've seen before include "Analphabetic" , "dunce" , "twenty seven?" , "Undereducated" , "one who can't read" .)