The most common and most likely answer to this crossword clue is the 6 letter word BOUNDS
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Buddy explains!

The straight part
We know that "Jumps/fences" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case jumps/fences = bounds.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 BOUNDS mean?
BOUNDS noun- (often used in plural) A boundary, the border which one must cross in order to enter or leave a territory.
- A value which is known to be greater or smaller than a given set of values.
- To surround a territory or other geographical entity.
- To be the boundary of.
- A sizeable jump, great leap.
- A spring from one foot to the other in dancing.
- A bounce; a rebound.
- To leap, move by jumping.
- To cause to leap.
- To rebound; to bounce.
- To cause to rebound; to throw so that it will rebound; to bounce.