The most common and most likely answer to this crossword clue is the 7 letter word PACKERS
I've seen this crossword clue in The Guardian
P
A
C
K
E
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S
Buddy explains!
The straight part
We know that "Travellers going without support/boxers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case travellers going without support/boxers = packers.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 PACKERS mean?
PACKERS noun- A person whose business is to pack things; especially, one who packs food for preservation
- A software program that compresses code or data.
- A ring of packing or a special device to render gastight and watertight the space between the tubing and bore of an oil well.
- An artificial penis or similar object worn by a drag king, trans man, etc., inside the trousers.
- An object inserted to hold a space open for the purpose of alignment; a spacer or shim.
- A kind of trunk for luggage.