Irish slang for a "Big Ignorant Fucker From Offaly" but feel free to substitute you city of choice...
It's especially handy when the BIFFO doesn't know you're insulting him (or her), and even better when they shorten it for themselves and asked to be called "Bif"

Noun. Big Ignorant Fucker From Offaly.

BIFFO is a derogatory term used to describe people from Co.Offaly. It is an acronym for Big Ignorant Fucker From Offaly. However, Offaly people being insecure about how ignorant they are somtimes like to change this around to give themselves a self-esteem boost. For example, the Tullamore Tribune once posted the headline Big Intelligent Fella's From Offaly over a picture of Brian Cowen (aka Leader of the BIFFO's) and Barack Obama (who is not from Offaly or related to the place in any significant way).

to hit, especially on rugby field

oh did I mention he is also a compulsive liar, see note above

Lad from Edinburgh now living in Fife who likes to rub his Cock against guys.

Someone who comes to work with a different fucked up hair style every day, then when he is at work rubs his cock against you or puts your computer off on you just to be a wank.