The most common and most likely answer to this crossword clue is the 4 letter word NABS
I've seen this crossword clue in Independent
N
A
B
S
More clues leading to the result NABS
Buddy explains!

The straight part
We know that "Catches" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case catches = nabs.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 NABS mean?
NABS verb- To seize, arrest or take into custody (a criminal or fugitive).
- To grab or snatch something.
- A single-serving package of crackers, usually filled with peanut butter. Snack crackers.