Exhausted; decadent (6)
I believe the answer is:
effete
This clue is a double definition.
'exhausted' is the first definition.
(I've seen this before)
'decadent' is the second definition.
(synonyms)
(Other definitions for effete that I've seen before include "Worn-out, decadent" , "Affected, over-refined" , "Feeble, lacking vitality" , "Feeble, weak" , "Over-refined and ineffectual" .)