Possible interpretations:
* Misspelling: It could be a misspelling of "bow," "boy," "wow," or other words.
* Slang: It might be a slang term used in a specific region or community.
* Imitation of a sound: It could be an attempt to represent a sound, like a cough or a sneeze.
To understand the meaning of "bwoh," you need more context. Please provide more information about where you saw or heard this word, or the situation in which it was used.