Shame a Christmas stealer is promoting church? (7)
I believe the answer is:
chagrin
'shame' is the definition.
(I know that chagrin is a type of embarrassment)
'a christmas stealer is promoting church?' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
'church?' could be 'ch' (common abbreviation) and 'ch' is found in the answer.
The remaining letters 'grin' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for chagrin that I've seen before include "anything but delight" , "Humiliation, mortification" , "Disappointment, exasperation" , "irritation?" , "Feeling of vexation or embarrassment" .)