A word used on the occasion when one person either forgets the name of another person in question, cannot be bothered using their real name or wants to make a spectacle of the person in a very boganish way.
This word is often used by tradesmen when speaking to either apprentices or fellow workers.
Builder:Oi keithy grab us the left handed screw driver.
Apprentice: righto mate.
Person1: hey thats old keithy isnt it?
person2: Yer, i saw him and oldmate the other day.