The most common and most likely answer to this crossword clue is the 7 letter word STAKING
I've seen this crossword clue in The Daily Telegraph
S
T
A
K
I
N
G
Buddy explains!
The straight part
We know that "Betting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case betting = staking.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 STAKING mean?
STAKING verb- To fasten, support, defend, or delineate with stakes.
- To pierce or wound with a stake.
- To put at risk upon success in competition, or upon a future contingency.
- To provide another with money in order to engage in an activity as betting or a business venture.
- An act of stabbing with a stake.