The most common and most likely answer to this crossword clue is the 10 letter word SNICKERING
I've seen this crossword clue in Financial Times
S
N
I
C
K
E
R
I
N
G
Buddy explains!

The straight part
We know that "Laughing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case laughing = snickering.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
SNICKERING verb- To emit a snicker, a stifled or broken laugh.
- To utter through a laugh of this kind.
- (of a horse) To whinny.
- The act of one who snickers.