A holy man enthralled by E European religious emissary (7)
I believe the answer is:
apostle
'european religious emissary' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'a holy man enthralled by e' is the wordplay.
'holy man' becomes 'st'.
'enthralled by' means one lot of letters goes inside another ('enthral' can mean 'capture').
'e' becomes 'pole' (I can't justify this - if you can you should give a lot more credence to this answer).
'st' put into 'pole' is 'postle'.
'a'+'postle'='APOSTLE'
(Other definitions for apostle that I've seen before include "One of Christ's 12 original disciples" , "who can handle a spoon?" , "Peter, perhaps" , "Ardent espouser of new system" , "Principal champion" .)