The most common and most likely answer to this crossword clue is the 10 letter word ABSTINENCE
I've seen this crossword clue in The Times
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More clues leading to the result ABSTINENCE
- Want to hold fool back when keeping dry
- Refraining from bunking off, saving money
- Leave money invested showing self-restraint
- Doing without six-pack, having drunk 9 etc
- Doing without money during time away
- During leave the money goes fast
- A habit that will keep one dry
- Want to carry can for teetotalism
- Need to come across can showing self-control
- Refraining from need to carry can
Buddy explains!

The straight part
We know that "when keeping dry" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case when keeping dry = abstinence.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 ABSTINENCE mean?
ABSTINENCE noun- The act or practice of abstaining, refraining from indulging a desire or appetite.
- The practice of self-denial; self-restraint; forebearance from anything.
- Self-denial; abstaining; or forebearance of anything.
- Delay of spending to accrue capital.