The most common and most likely answer to this crossword clue is the 11 letter word SCUTTLEBUTT
I've seen this crossword clue in The Times
S
C
U
T
T
L
E
B
U
T
T
More clues leading to the result SCUTTLEBUTT
Buddy explains!

The straight part
We know that "Dirt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dirt = scuttlebutt.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 SCUTTLEBUTT mean?
SCUTTLEBUTT noun- A butt with a scuttle, a keg of drinking water with a hole cut in it, on board ship.
- Gossip, rumour, idle chatter.