Soccer official, Italian, works to improve (5)
I believe the answer is:
refit
'works to improve' is the definition.
(construction work to improve something)
'soccer official italian' is the wordplay.
'soccer official' becomes 'ref' (short for referee).
'italian' becomes 'it' (abbreviation for Italian).
'ref'+'it'='REFIT'
(Other definitions for refit that I've seen before include "Overhaul (ship)" , "Mend" , "Repair or re-equipping of a ship or shop?" , "Equip anew" , "Refurbishment (of ship)" .)