Start-of-year return for corrupt concierge (7)
I believe the answer is:
janitor
'concierge' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for janitor that I've seen before include "(In Scotland) school caretaker" , "One employed to clean and maintain a building" , "Caretaker or doorkeeper" , "Caretaker (mainly US)" , "Person looking after building" .)