The most common and most likely answer to this crossword clue is the 6 plus 3 letter word SACRED COW
I've seen this crossword clue in The Guardian
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More clues leading to the result SACRED COW
- You can’t have a go at this bloody bully after school turned around
- Scared, possibly by bully — one given undue respect
- Institution seen as above criticism, but lower in religion?
- Understood about belief accepting Conservative idol
- Races around Washington, now dismissing new inviolate institution
- It’s not open to question, thus load rough cedar into barge
- Conservation area by pub that’s above criticism
- A person beyond criticism is ridiculously scared with women's company inside
- Venerated institution worried about advancing bully
- Custom immune to criticism from airman blushing aboard boat
Buddy explains!

The straight part
We know that "You can’t have a go at this" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case you can’t have a go at this = sacred cow.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.