The most common and most likely answer to this crossword clue is the 9 letter word LARCENOUS
I've seen this crossword clue in The Daily Telegraph
L
A
R
C
E
N
O
U
S
More clues leading to the result LARCENOUS
- Unusually clear — having some sense in committing crime
- Clear criminal talent, working as a thief
- Strangely unrecognisable without being criminal
- Arson clue possibly revealing criminal
- Likely to steal intelligence after clear out
- Criminal rules a con could be light-fingered
- Son: a cruel, wicked criminal
- Nature of theft is so unclear, unfortunately
Buddy explains!

The straight part
We know that "light-fingered" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case light-fingered = larcenous.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.