Material displayed by salesperson in church (5)
I believe the answer is:
crepe
'material' is the definition.
(I know that crepe is a type of material)
'salesperson in church' is the wordplay.
'salesperson' becomes 'rep' (sales rep).
'in' is an insertion indicator.
'church' becomes 'CE' (Church of England).
'rep' placed within 'ce' is 'CREPE'.
'displayed by' is the link.
(Other definitions for crepe that I've seen before include "Soft thin fabric with a crinkled surface" , "French dish" , "Crinkled paper or fabric" , "Crinkled fabric - black armband - thin pancake" , "Crinkly fabric and French pancake" .)