I genuinely don't know which word he's talking about, either. I mean I know plenty of 4-letter words but none that Australia has cornered the market on, to my knowledge.
Australians have a meme they say cunt more than other cultures.
Analytically the UK is actually higher I believe, but they are just to cool to brag about it - https://onemilliontweetmap.com/?search=cunt (Possibly a bit off atm because of elections)