Actor, terrible at reading (9)
I believe the answer is:
tragedian
'actor' is the definition.
(tragedian is a kind of actor)
'terrible at reading' is the wordplay.
'terrible' is an anagram indicator.
'at'+'reading'='atreading'
'atreading' anagrammed gives 'TRAGEDIAN'.
(Other definitions for tragedian that I've seen before include "Egad, I rant about dramatic actor" , "actor in Macbeth?" , "Dramatist" , "A great din (anag) - actor" , "Serious actor" .)