Character in company in busy city (5)
I believe the answer is:
cairo
'busy city' is the definition.
'cairo' can be an answer for 'city' (Cairo is an example). I'm not certain of the 'busy' bit.
'character in company' is the wordplay.
'character' becomes 'air' (air can mean a character or mood).
'in' means one lot of letters goes inside another.
'company' becomes 'co' (abbreviation).
'air' going inside 'co' is 'CAIRO'.
'in' is the link.
Can you help me to learn more?
(Other definitions for cairo that I've seen before include "Port upstream from the Nile delta" , "Egyptian capital" , "Al Qahira" , "African city" , "City near the Nile delta" .)