The most common and most likely answer to this crossword clue is the 8 letter word AUDACITY
I've seen this crossword clue in The Times
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More clues leading to the result AUDACITY
- Including account in financial check, said why that's bold
- Boldness of a superior daughter coming to a place like London
- Financial check covering account year — that’s daring
- Garden girl heading off to a big town — such boldness!
- Daring publicity surrounding university – Oxford and Cambridge for example
- Girl's move over one year in arrogance
- Review entertaining account by the Yankee with courage
- Give Australian money to a metro enterprise
- Daring dean occasionally seen in a university town
- Recklessness of car almost hitting a centre of population
Buddy explains!

The straight part
We know that "that's bold" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that's bold = audacity.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 AUDACITY mean?
AUDACITY noun- Insolent boldness, especially when imprudent or unconventional.
- Fearlessness, intrepidity or daring, especially with confident disregard for personal safety, conventional thought, or other restrictions.