The most common and most likely answer to this crossword clue is the 9 letter word REMAINDER
I've seen this crossword clue in The Daily Telegraph
R
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M
A
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R
More clues leading to the result REMAINDER
- Prompt to include a rest
- One not wanting to leave, accepting day's rest
- Jogger carrying a cut-price book
- Balance poor in paper’s last piece, dear me!
- What helps one remember to snatch a rest
- Jogger welcoming a rest
- Jogger grabbing a rest
- Allen at the start breaks cue and rest
- Cue, holding a rest
- Diamonds hidden by one not wanting to leave what’s left
Buddy explains!

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 REMAINDER mean?
REMAINDER noun- A part or parts remaining after some has/have been removed.
- The amount left over after subtracting the divisor as many times as possible from the dividend without producing a negative result. If (n) (dividend) and d (divisor) are integers, then (n) can always be expressed in the form n = dq + r, where q (quotient) and r (remainder) are also integers and 0 ≤ r < d.
- The number left over after a simple subtraction
- Excess stock items left unsold and subject to reduction in price.
- An estate in expectancy which only comes in its heir's possession after an estate created by the same instrument has been determined
- To mark or declare items left unsold as subject to reduction in price.
- Remaining.