cuz its scarry
People say 'boo' on Halloween because it is considered as a 'spooky' time, usually pretending to scare someone.
Boo niey ching
boo
Boo!
because back then it ALWAYS SCARED PEOPLE!!! :)
From the scars that the Bu-Bo-Nic plague left.
In Hawaiian, "boo boo" could be translated as "hau'oli" which means "sore" or "injured."
Boo!
"Tengo un boo-boo." or "Tengo un dolor."
Peek a boo
Where I'm from people say "bougie". Pronounced boo-zhee.
"No me ignores boo"