a native or inhabitant of Australia
"The aussie waved hello as he walked past the shop on his way to work in Sydney."
An Australian.
"The aussie traveler waved hello as he boarded the flight to Sydney."
Australian.
"The aussie accent was immediately noticeable when he arrived in London."
Australia (now uncommon except in sporting chants).
"The crowd roared their aussie cheers as the home team scored the winning goal."
The word "aussie" comes from combining "Aus," short for Australia, with the suffix "-sie." It was originally used as a casual nickname for someone from Australia.