Approval withheld in retreat? (4)
I believe the answer is:
nook
'retreat?' is the definition.
(nook is a kind of retreat)
'approval withheld' is the wordplay.
I cannot really understand how this works, but
'approval' could be 'ok' (OK is an example) and 'ok' is found within the answer.
The remaining letters 'no' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for nook that I've seen before include "Recess or cranny" , "Comfortable corner" , "shady retreat" , "Small space" , "Corner - narrow recess" .)