The most common and most likely answer to this crossword clue is the 7 plus 3 letter word DERRING -DO
I've seen this crossword clue in The Guardian
D
E
R
R
I
N
G
-
D
O
Buddy explains!

The straight part
We know that "bold actions" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bold actions = derring -do.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 DERRING -DO mean?
DERRING -DO noun- Valiant deeds in desperate times.
- Brave and adventurous (albeit often reckless) actions.