Examine penny hidden by trendy religious group (7)
I believe the answer is:
inspect
'examine' is the definition.
(I know that inspect is a more specific form of examine)
'penny hidden by trendy religious group' is the wordplay.
'penny' becomes 'p' (short for pence).
'hidden by' is an insertion indicator (inserted letters are hidden inside).
'trendy' becomes 'in' ('in' can mean fashionable).
'religious group' becomes 'sect' (eg a religious sect).
'in'+'sect'='insect'
'p' inserted into 'insect' is 'INSPECT'.
(Other definitions for inspect that I've seen before include "Check" , "Examine officially" , "vet" , "Scrutinise" , "Go over" .)