'Beware!' Post section's review for Carmen ? (5)
I believe the answer is:
opera
'carmen ?' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's an association between them I don't understand?
'beware post section's review' is the wordplay.
'section's' says the answer is hidden in the clue (I've seen 'section' mean this).
'review' shows that the letters should be reversed in order.
'arepo' is hidden within 'beware post'.
'arepo' backwards is 'OPERA'.
'for' acts as a link.
(Other definitions for opera that I've seen before include "Grand or comic work?" , "Comic or grand entertainment?" , "Verdi work?" , "Eg, La forza del destino" , "One at the Met" .)