The most common and most likely answer to this crossword clue is the 2 plus 4 letter word EX CONS
I've seen this crossword clue in Financial Times
E
X
C
O
N
S
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.
Crossword Answer definitions
EX CONS noun- A former prisoner.