The most common and most likely answer to this crossword clue is the 3 plus 4 letter word PRO BONO
I've seen this crossword clue in Financial Times
P
R
O
B
O
N
O
More clues leading to the result PRO BONO
- Boo porn that’s given out free in US
- In favour of U2’s singer not getting any money
- Enquiry ended early on ring with no charges
- Not requiring payment for singer
- Half probably on oxygen in such charitable cases
- Professional singer performed for public benefit
- Supporting singer-songwriter for the public good
- One’s paid pop star for nothing
- Giving free services for Irish singer
- Parking hold up in operation over not being paid
Buddy explains!

The straight part
We know that "for the public good" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case for the public good = pro bono.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.