Green’s Dictionary of Slang

(Aus.) an admirable person or object, thus boskeress .

1901		Western Champion (Barcaldine, Qld) 4 Nov. 6/1: A new slang word has been invented in Sydney by the ‘push.’ Everything which particularly appeals to the fancy of the talent is spoken of as ‘bosker.’ At the football matches one hears ‘Ain’t ’e a bosker’ instead of, as formerly, ‘Ain’t ’e a champeon’.
1903		Eve. Post (Wellington) 23 Mar. 5: [advert] This Week’s Programme a ‘Boshker’.
1904		Sydney Sportsman (Surry Hills, NSW) 18 May 3/6: My friends think they [i.e. home-penned limericks] are ‘boskers,’ but I don’t want to build myself up. I think they are ‘beskerinos,’ and hope you concur.
1906		Eve. Post (Wellington) 21 Sept. 7: [advert] That’s where mother got those Pants. I tell you Boshker’s, too!
1908		Truth (Wellington) 2 May 2/5: She was a bosker to look at.
1908		Gadfly (Adelaide) 27 May 6/3: And skating being quite a suitable pastime for both sexes, why also shouldn’t the Great Boskeress be given a chance to come forward and assert herself ?
1914		Nambour Chron. (Qld) 18 Dec. 2/6: Supper was served at midnight, and the gathering dispersed voting the first annual breakfast a ‘bosker’.
1915		Mirror of Aus. (Sydney) 25 Dec. 6/1: At least one supporter thought Adela quite beautiful. One beery gentleman gurgled, ‘She’s a boshker’.
1922		T.E. Spencer ‘Liza’ in Budgeree Ballads 83: Lumme Liza! You’re a bosker! You’re a jewel!
1964		B. Hesling Dinkumization or Depommification 134: Bloody bosker! . . . Oh, good show!
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 55: In fact it was none other than an old hometown adversary in Detective Sergeant Clyde ‘Bosker’ Boskins from Darlinghurst police.