Bruh

Bruh when taken on its own means nothing, it is entirely dependant upon the context of a situation for meaning. It's similar to something like an exclamation mark, or using all caps in that way. Using it in a sentence, or even just on its own, typically adds some kind of emotion of confusion or disbelief to a statement. For instance, "what?" can have many meanings based on context, but saying "bruh what?" specifically implies that the cause for confusion was because the original statement itself made no sense.

"What is Obama's last name?"
"Bruh

"Bruh I got an A on that essay"

"Enjoy your meal"
"You too"
"Bruh"