The most common and most likely answer to this crossword clue is the 5 letter word VAULT
V
A
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T
Buddy explains!

The straight part
We know that "Safe/jump" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case safe/jump = vault.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 VAULT mean?
VAULT noun- An arched masonry structure supporting and forming a ceiling, whether freestanding or forming part of a larger building.
- Any arched ceiling or roof.
- Anything resembling such a downward-facing concave structure, particularly the sky and caves.
- The space covered by an arched roof, particularly underground rooms and church crypts.
- Any cellar or underground storeroom.
- Any burial chamber, particularly those underground.
- The secure room or rooms in or below a bank used to store currency and other valuables; similar rooms in other settings.
- A piece of apparatus used for performing jumps.
- A gymnastic movement performed on this apparatus.
- An encrypted digital archive.
- An underground or covered conduit for water or waste; a drain; a sewer.
- An underground or covered reservoir for water or waste; a cistern; a cesspit.
- A room employing a cesspit or sewer: an outhouse; a lavatory.
- To build as, or cover with a vault.
- An act of vaulting, formerly by deer; a leap or jump.
- An event or performance involving a vaulting horse.
- To jump or leap over.
- A turning; a time (chiefly used in phrases signifying that the part is to be repeated).
- A volte
- A turning point or point of change in a poem, most commonly a sonnet.