Green’s Dictionary of Slang

(Aus.) a new immigrant.

1887		Bulletin (Sydney) 26 Feb. 12: He was a new-chum, a regular johnny-raw.
1906		Bulletin (Sydney) 28 June 14/2: New chums were originally called Johnny Raws. From that it got to Jacky Raw. And from Jacky Raw to Jackeroo is but a slip of the tongue.
1908		Aus. Mag. (Sydney) Nov. 1251/2: A ‘jackeroo’ (a new chum on a station out for colonial experience) is supposed to be ‘Jacky Raw’ with a kangaroo’s tail to it as it were [AND].
1951		Mail (Adelaide) 1 Dec. 2s/5: Australians have bult up a vocabulary of some 7,000 slang words [...] Jacky Raw—A new chum.
1955		N. Pulliam I Travelled a Lonely Land (1957) 235/1: johnny raw (jacky raw, jimmy raw) – a new friend.
1962		D. McLean World turned upside Down 79: What th’ ell’s th’ matter with you today? Y’ moonin’ about like a jacky raw [AND].