Move slowly and gradually in church (4)
I believe the answer is:
inch
'move slowly and gradually' is the definition.
'in church' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'in'+'ch'='INCH'
(Other definitions for inch that I've seen before include "Irish island" , "Edge along" , "Edge towards" , "2.45 cm" , "Twenty five point four millimetres" .)