Develop some closure with Italian leader (5)
I believe the answer is:
educe
'develop' is the definition.
(I've seen this in another clue)
'some closure with italian leader' is the wordplay.
'closure' says to take the final letters (the letter which closes the word).
'with' says to put letters next to each other.
'italian leader' becomes 'duce' (Benito Mussolini was known as Il Duce).
The last letter of 'some' is 'e'.
'e'+'duce'='EDUCE'
(Other definitions for educe that I've seen before include "Infer" , "Extract" , "Draw forth" , "Bring out, develop" , "Bring out (something)" .)