Well, the Aussie language is about 50% slang... some of the more well known ones.
Fair Dinkum - Can be used in several ways.
Are you fair dinkum? = In its question form, is roughly Equivalent to the American 'Are you for real?'
Fair Dinkum! = As a statement, it means 'That's amazing/incredible!' or 'How annoying!' depending on the context.
You gotta be fair-dinkum kidding me! = Here, it serves as a replacement for any number of expletives.
Pom = Our affectionate name for the English, especially when sports are involved. ie 'The poms copped a
shilacking in the Ashes (a two yearly cricket competition between England and Australia)'
Footy = Football, one of any of the four codes we play here (Rugby, League, Soccer and Aussie Rules).
Dunny, loo, **** house = toilet
'built like a brick **** house' = describes a particularly bulked up, solidly built person - often used in reference to a football player.
tanked, sloshed = drunk
can't be stuffed = Can't be bothered.