The most common and most likely answer to this crossword clue is the 12 letter word SHORT-CHANGE
I've seen this crossword clue in The Times
S
H
O
R
T
-
C
H
A
N
G
E
Buddy explains!
The straight part
We know that "swindle" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case swindle = short-change.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 SHORT-CHANGE mean?
SHORT-CHANGE verb- To defraud someone by giving them less change than they should be given after a transaction.
- (by extension) To deprive someone of something for which they paid.
- To make disadvantaged by design.