Phrase used as a common insult in schools around the country, also used as a greeting in the non-affulent areas of most towns. In a strong bristolian accent, this is pronounced yer ma.
Oof: Oi chris!
Chris: YERRRRRRRRR MAAAAAAAAAAAAA
Derived from Hoof, can be used to describe a mistake, or can be used as a nickname for slightly unintelligent people
I oofed that up,