Profiteering concerns Senate, essentially carousing in the wings (9)
I believe the answer is:
mercenary
'wings' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for mercenary that I've seen before include "Professional soldier hired by foreign country" , "Acting for money" , "Soldier of fortune" , "Soldier for hire" , "One who fights for foreign country for pay" .)