Entertain European in Italian restaurant (5)
I believe the answer is:
treat
'entertain' is the definition.
(thesaurus)
'european in italian restaurant' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'in' means one lot of letters goes inside another.
'italian restaurant' becomes 'trat' (I've seen this in other clues).
'e' going into 'trat' is 'TREAT'.
(Other definitions for treat that I've seen before include "Behave towards" , "Medicate" , "Pay for - minister to - deal with" , "Source of gratification" , "Entertain and pick up the tab" .)