Belittle chapter provided by each writer (7)
I believe the answer is:
cheapen
'belittle' is the definition.
(I've seen this in another clue)
'chapter provided by each writer' is the wordplay.
'chapter' becomes 'ch'.
'provided by' is a charade indicator (letters next to each other).
'each' becomes 'ea' (abbreviation).
'writer' becomes 'pen' (something which writes).
'ch'+'ea'+'pen'='CHEAPEN'
(Other definitions for cheapen that I've seen before include "Decry or devalue" , "Tried" , "discount" , "Reduce worth, degrade" , "Debase" .)