The most common and most likely answer to this crossword clue is the 5 letter word XEROX
I've seen this crossword clue in Independent
X
E
R
O
X
More clues leading to the result XEROX
Buddy explains!

The straight part
We know that "Perhaps run off" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case perhaps run off = xerox.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 XEROX mean?
XEROX noun- A photocopy.
- A photocopier.
- To make a paper copy or copies by means of a photocopier.