An abbreviation for; You Big
Nut.
Noun,
Slang.
1. A term used to describe someone who is clumsy, off-kilter, or somewhat foolish.
On their way to lunch...
Mr.
Valentine: Mr. Malchow, I think I forgot my wallet at the office.
Mr. Malchow: Well, why'd you do that YBN?
Mr.
Valentine: Because I'm a big
nut.