The most common and most likely answer to this crossword clue is the 7 letter word GABFEST
I've seen this crossword clue in Independent
G
A
B
F
E
S
T
More clues leading to the result GABFEST
Buddy explains!
The straight part
We know that "Mostly gag most about loud emitter of much gas? (7)/emitter of much gas?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mostly gag most about loud emitter of much gas? (7)/emitter of much gas? = gabfest.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 GABFEST mean?
GABFEST noun- An occasion (such as a meeting) where people talk at length.