Dinkum

Australian English is a major variety of the English language spoken throughout Australia. Most of the vocabulary of Australian English is shared with British English, though there are notable differences. The vocabulary of Australia is drawn from many sources, including various dialects of British English as well as Gaelic languages, some Indigenous Australian languages, and Polynesian languages.

One of the first dictionaries of Australian slang was Karl Lentzner's Dictionary of the Slang-English of Australia and of Some Mixed Languages in 1892. The first dictionary based on historical principles that covered Australian English was E. E. Morris's Austral English: A Dictionary of Australasian Words, Phrases and Usages (1898). In 1981, the more comprehensive Macquarie Dictionary of Australian English was published. Oxford University Press published their own Australian Oxford Dictionary in 1999, as a joint effort with the Australian National University. Oxford University Press also published The Australian National Dictionary.

Australian English term Outback means a "remote, sparsely-populated area". Jackaroo is a type of agricultural worker.

A Battler is a person with few natural advantages, who works doggedly and with little reward, who struggles for a livelihood and who displays courage. The first citation for this comes from Henry Lawson in While the Billy Boils (1896):

I sat on him pretty hard for his pretensions, and paid him out for all the patronage he'd worked off on me... and told him never to pretend to me again he was a battler.

...
Wikipedia