All in (5)
I believe the answer is:
spent
'all in' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for spent that I've seen before include "Drained of energy - or paid out" , "Worn out having paid out money." , "Burned-out" , "Used up; exhausted" , "Worn out - after shopping?" .)