What's left (9)
'what's left' is the definition.
(residue means what's left behind)
This is all the clue.
(Other definitions for residue that I've seen before include "grounds" , "Something remaining" , "It remains after other parts have been taken away" , "Matter left behind after other parts have been taken away" , "Dire use of what is left over" .)
'what's left' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for remainder that I've seen before include "butt" , "Unsold copy of book" , "book going cheap" , "Surplus" , "It's left over after division" .)