Grandee in AGM if breaking up company (9)
I believe the answer is:
magnifico
'grandee' is the definition.
(I've seen this before)
'in agm if breaking up company' is the wordplay.
'breaking up' indicates an anagram.
'company' becomes 'co' (abbreviation).
'in'+'agm'+'if'='inagmif'
'inagmif' with letters rearranged gives 'magnifi'.
'magnifi'+'co'='MAGNIFICO'
(Other definitions for magnifico that I've seen before include "great one" , "VIP" , "grandee" .)