Green’s Dictionary of Slang

(Aus./UK) excellent!

1960		N. Hilliard Maori Girl 181: I think they’re beauty! [Ibid.] 185: She spilt some sugar over the tablecloth. ‘Beauty! I’m going to get a lot of money!’.
1966		B. Reckord Skyvers I ii: cragge: Goal. adams (hugging cragge): Beauty.
1986		T. Winton That Eye, The Sky 130: I get six of the best to show how much he doesn’t wanna see me. April Fool. Beaudy.
1996		Penguin Bk of More Aus. Jokes 137: ‘Bewdy,’ says the drunk and, taking his prize, he staggers off.
2003		McGill Reed Dict. of N.Z. Sl. 18: beaudy/beaut/beauty/beautee/bewdy Appreciative exclamation, also used as an adjective or noun.
2006		P. Carey Theft 75: Beauty, I thought, that’s done.
2015		N. Cummins Tales of the Honey Badger [ebook] You beauty, holiday!