Rank he lost in revolutionary Red China (6)
I believe the answer is:
rancid
'rank' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rancid that I've seen before include "Like fat that's gone off" , "Sour - smelling bad" , "(Of butter) stale" , "Sour, rotting" , "Smelly and going bad" .)