Red Queen replaces China's leader (5)
I believe the answer is:
ruddy
'red' is the definition.
('ruddy' can be a synonym of 'red')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for ruddy that I've seen before include "Rosy" , "Healthily red in face" , "Rubicund" , "Florid (of face)" , "Dratted" .)