The most common and most likely answer to this crossword clue is the 5 letter word RELIT
I've seen this crossword clue in Financial Times
R
E
L
I
T
More clues leading to the result RELIT
- Workman on roof maybe starting at bottom got going again
- One leaving retail organisation set off again
- Centre of party hat, when turned round, illuminated again
- Roof worker returning with new enthusiasm?
- Some consider elite got going again
- After setback high-level worker perhaps is fired up again
- Roofer performing climb gets fired again
- Cook let rip endlessly to get fired again
- Roofing operative goes around burning again
- 2, cycling, got going again
Buddy explains!

The straight part
We know that "set off again" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case set off again = relit.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 RELIT mean?
RELIT verb- To light or kindle anew.
- To render again with different simulated lighting conditions.