Compound rate's void in Ukraine (4)
I believe the answer is:
urea
'compound' is the definition.
(urea is a kind of compound)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for urea that I've seen before include "It's produced by piddling" , "wee substance?" , "Waste product of mammals" , "Compound found in urine, synthesised as a fertiliser" , "Waste matter" .)