The most common and most likely answer to this crossword clue is the 6 letter word DOSSER
I've seen this crossword clue in Financial Times
D
O
S
S
E
R
More clues leading to the result DOSSER
Buddy explains!

The straight part
We know that "Vagrant" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vagrant = dosser.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 DOSSER mean?
DOSSER noun- Someone who dosses, someone known for avoiding work.
- A homeless and jobless person.
- One who lodges in a doss-house.
- A pannier or basket.
- A hanging tapestry; a dorsal.