The most common and most likely answer to this crossword clue is the 7 letter word TAM-TAM
I've seen this crossword clue in The Times
T
A
M
-
T
A
M
Buddy explains!
The straight part
We know that "Gong" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gong = tam-tam.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 TAM-TAM mean?
TAM-TAM noun- A flat gong (without knob) that is struck with a felt-covered hammer.
- To beat on a drum.