Go away and triumph over Italian (4,2)
I believe the answer is:
beat it
'go away' is the definition.
(impolite way of telling someone to leave)
'triumph over italian' is the wordplay.
'triumph over' becomes 'beat'.
'italian' becomes 'it' (abbreviation for Italian).
'beat'+'it'='BEAT IT'
'and' is the link.
(Other definitions for beat it that I've seen before include "leave" , "Scarper" , "try out drum kit?" , "Scram, take a powder" , "Slang order to go away, get lost" .)