* Sound: It could be a sound effect or onomatopoeia representing something like a bird's call, a cough, or a grunt.
* Slang or informal term: It might be a slang word or informal expression in a particular region or community, but without context, it's impossible to know its meaning.
* Misspelling: It could be a misspelling of another word.
To figure out what "Gwah" means, you need more context:
* Where did you hear or see it? (book, movie, conversation, etc.)
* What was the situation? (What was happening around the time it was said?)
* Who said it? (Could they be from a specific region or culture?)
Please provide more information so I can help you understand the meaning of "Gwah."