Meloni's opener: "Trump's intelligence? Zero!" (4)
I believe the answer is:
ciao
'meloni's opener trump's' is the definition.
I can't judge whether this definition defines the answer.
'intelligence? zero' is the wordplay.
'intelligence?' becomes 'cia' (Central Intelligence Agency).
'zero' becomes 'O' (O resembles 0).
'cia'+'o'='CIAO'
Can you help me to learn more?
(Other definitions for ciao that I've seen before include "European's greeting" , "Italian's so long" , "Italian salutation" , "Buongiorno o arrivederci" , "See you in Italy" .)