Nick books put in Northern church (5)
I believe the answer is:
notch
'nick' is the definition.
('notch' can be a synonym of 'nick')
'books put in northern church' is the wordplay.
'books' becomes 'ot' (Old Testament).
'put in' is an insertion indicator.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'church' becomes 'ch' (common abbreviation).
'n'+'ch'='nch'
'ot' put inside 'nch' is 'NOTCH'.
(Other definitions for notch that I've seen before include "Indentation, nick" , "Salad plant, garnish" , "Tallying incision" , "Dent" , "V-shaped incision" .)