Dull gospel writer wanting cut (4)
I believe the answer is:
matt
'dull' is the definition.
('matt' can be similar in meaning to 'dull')
'gospel writer wanting cut' is the wordplay.
'gospel writer' becomes 'matthew' (I've seen this before).
'wanting' indicates named letters should be taken away (to want something can mean to lack it or need it).
'cut' becomes 'hew' (I've seen this before).
'matthew' with 'hew' taken out is 'MATT'.
(Other definitions for matt that I've seen before include "book" , "Dull, not shiny" , "- Lucas (Little Britain)" , "Not glossy" , "Telegraph cartoonist" .)