OK, there's nothing left (3,5)
I believe the answer is:
all right
'nothing left' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for all right that I've seen before include "Yes - adequate" , "Very well, as you wish" , "Very well, I'll do it" , "Agreed" , "Safe - adequate" .)