Relation ran up with allowance (9)
I believe the answer is:
narration
'relation' is the definition.
(thesaurus)
'ran up with allowance' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'with' is a charade indicator (letters next to each other).
'allowance' becomes 'ration' (I've seen this before).
'ran' back-to-front is 'nar'.
'nar'+'ration'='NARRATION'
(Other definitions for narration that I've seen before include "telling" , "Voice-over in film" , "Process of storytelling" , "Story" , "Account of events" .)