Check this out - new president-elect informally addressed city (6)
I believe the answer is:
london
'city' is the definition.
(London is an example)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for london that I've seen before include "Where Boris Johnson might be" , "City of Piccadilly" , "US writer" , "City for the odd non-old" , "UK Capital city" .)