A storyteller reverting to abuse (4)
I believe the answer is:
liar
'a storyteller' is the definition.
(someone telling lies)
'reverting to abuse' is the wordplay.
'reverting' says the letters should be written in reverse.
'to abuse' becomes 'rail' (railing is a kind of abusing).
'rail' in reverse letter order is 'LIAR'.
(Other definitions for liar that I've seen before include "Dissembler" , "one telling a story" , "Teller of fibs" , "Worse than a thief" , "Rail at a prevaricator" .)