The most common and most likely answer to this crossword clue is the 4 letter word CIAO
I've seen this crossword clue in Financial Times
C
I
A
O
More clues leading to the result CIAO
- Firm welcomes one with a greeting
- Activator, oddly inactive for so long
- Italian company on greeting
- Greeting that’s international, accepted in company
- Spies love an informal welcome
- First or last word from Italian in Chicago, oddly
- Hear dog for so long
- All the best food is caught
- Greeting government agency circular
- People of intelligence love to have the last word
Buddy explains!

The straight part
We know that "Berlusconi’s farewell" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case berlusconi’s farewell = ciao.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CIAO mean?
CIAO noun- A greeting or farewell using the word "ciao".
- Hello, hi.
- Bye, goodbye.