It can mean many things.
B: Bro (Hey man.)
R: Randomness (bruh.)
U: Ugly (Bruuuuuuh.)
H: Happy (Bruh, omg!)
Sally: BRUH! Last night was fun.
Jen: Bruuuuuh, you looked horrible, tho.
S: Bruh, Idc.
A reaction word, oftentimes used in reaction to an unfunny or disappointing thing, to convey displeasure.
"Oh shit I dropped my ice cream"
"Bruh"
bruh is bruh and you maybe a bruh
fortnite is a bruh.
life is a bruh.
yo mama is a bruh.
me: bruh
bff: bruh bruh and then i just said bruh and i really don't give a bruh
Bruh is a word used in an ‘omfg your such an idiot’ moment
Brad:did u know that giraffes can’t fly?
Chad: Bruh