Degenerate couples swapped in centre of blue room (4)
I believe the answer is:
roue
'degenerate' is the definition.
(thesaurus)
'couples swapped in centre of blue room' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is present in the answer.
The remaining letters 'rue' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for roue that I've seen before include "A French rake, dissipated fellow" , "Libertine male" , "Reckless spender" , "Casanova" , "Debauchee" .)