Flattering City chap and son may be misguided (11)
I believe the answer is:
sycophantic
'flattering' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for sycophantic that I've seen before include "tending to fawn" , "Crawling" , "Canaries were once so" , "Toadyish" , "flattery" .)