Gentleman rising after society girl remains (6)
I believe the answer is:
debris
'remains' is the definition.
(I've seen this before)
'gentleman rising after society girl' is the wordplay.
'gentleman' becomes 'sir' (I've seen this before).
'rising' shows that the letters should be reversed in order (going up in a down clue).
'after' means one lot of letters go next to another.
'society girl' becomes 'deb' (I've seen this before).
'sir' back-to-front is 'ris'.
'ris' after 'deb' is 'DEBRIS'.
(Other definitions for debris that I've seen before include "Refuse, litter" , "Broken remains" , "aftermath of wild reception?" , "Remains - wreckage" , "Rebids for rubble" .)