Early brilliance before business at Metropolis (9)
I believe the answer is:
precocity
'early brilliance' is the definition.
'precocity' can be an answer for 'brilliance' (thesaurus). I'm not sure about the 'early' bit.
'before business at metropolis' is the wordplay.
'before' becomes 'pre' (prefix meaning 'before').
'business' becomes 'co' (short for company).
'at' means one lot of letters go next to another.
'metropolis' becomes 'city' (synonyms).
'pre'+'co'+'city'='PRECOCITY'
Can you help me to learn more?
(Other definitions for precocity that I've seen before include "Of child, state of having knowledge too soon" , "Boy wonder quality" , "Premature development" , "Forwardness" , "early flowering" .)