He wants to go back in politics (11)
I believe the answer is:
reactionary
This could be a double definition.
'he wants to' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'back in politics' is the second definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'go' is the link.
Can you help me to learn more?
(Other definitions for reactionary that I've seen before include "right-winger?" , "Opposing progress or reform" , "Ultra-conservative" , "Diehard" , "No progressive" .)