Plays down in the dumps around ruin, in retrospect (6)
I believe the answer is:
dramas
'plays' is the definition.
('drama' can be a synonym of 'play')
'down in the dumps around ruin in retrospect' is the wordplay.
'down in' indicates putting letters inside.
'the dumps around' becomes 'sad' (I can't justify this - if you can you should give a lot more credence to this answer).
'ruin' becomes 'mar' (I've seen this before).
'in retrospect' shows that the letters should be reversed in order.
'sad' enclosing 'mar' is 'samard'.
'samard' backwards is 'DRAMAS'.
Can you help me to learn more?
(Other definitions for dramas that I've seen before include "Tragic situations" , "crises" , "Theatrical plays" , "works" , "sensations" .)