The most common and most likely answer to this crossword clue is the 5 letter word BELCH
I've seen this crossword clue in The Guardian
B
E
L
C
H
More clues leading to the result BELCH
- Check on ringer endlessly and forcibly expel
- Violently eject leaders of British Eurosceptics leaving Cameron happy
- Sir Toby's expulsion after meal?
- He’s primarily boozing, envying large companion in play
- Release of gas bomb El Chapo carries
- Forcibly expel ringer leaving one large church
- Rude noise as part of rebel chant
- Gas escape from case of butane left by church
- A Winter’s Tale character to discharge
- Expel the Spanish in Belgium and Switzerland
Buddy explains!

The straight part
We know that "Gas escape" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gas escape = belch.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 BELCH mean?
BELCH noun- The sound one makes when belching.
- Malt liquor.
- To expel (gas) loudly from the stomach through the mouth.
- To eject or emit (something) with spasmodic force or noise.
- To be ejected or emitted (from something) with spasmodic force or noise.