Comedic offshoot of the phrase "Gay Boy".
A putdown, meaning that the subject is not cool, the odd one out, or doing something the speaker does not like.
Also can be used to describe a 1997 Nissan Altima in Westland, Michigan.
Al-"Hey man, can I use your car?"
Jon-"No way bro, you'll crash it!"
Al-"What a GayBuay!"
"You drivin' the GayBuay?"