Possibly wry expression of chagrin? (4)
I believe the answer is:
grin
'possibly wry expression' is the definition.
'grin' can be an answer for 'expression' (I have seen 'Facial expression ' mean 'grin' so perhaps 'expression' could also mean 'grin'). I'm not certain of the 'possibly wry' bit.
'chagrin?' is the wordplay.
'GRIN' is hidden within the letters.
But, I am unsure how this is indicated.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for grin that I've seen before include "Happy expression" , "show ivories happily with it" , "Smile while pulling back the lips" , "Accept with good grace - . . . . and bear it" , "Smile - all that could be seen of the vanishing Cheshire Cat" .)