The most common and most likely answer to this crossword clue is the 3 plus 3 letter word SET OFF
I've seen this crossword clue in Independent
S
E
T
O
F
F
More clues leading to the result SET OFF
- Southeastern upper-class type to embark on journey
- With drugs around, posh chap exploded
- . Posh chap from Home Counties making you explode
- Leave Home Counties with well-heeled man
- Mount and start on a journey
- Start to rubbish efforts right away
- Initiate display
- Start to complement
- Initiate display
- Leave as contrast
Buddy explains!

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 SET OFF mean?
SET OFF noun- That which is set off against another thing; an offset.
- That which is used to improve the appearance of anything; a decoration; an ornament.
- A counterclaim; a cross debt or demand; a distinct claim filed or set up by the defendant against the plaintiff's demand.
- An offset.