Green’s Dictionary of Slang

1. (Aus.) an inhabitant of the bush.

1827

Australian (Sydney) 4 July 3/3: Many a Sydney ‘swell’ and a Windsor ‘blade‘ and a ‘busher‘ [...] showed off their several ‘gustos’ in cut and come again.

2. (US) an amateur, an unsophisticated person; thus bush v., to act in a second-rate manner; also attrib.

1909		Van Loan ‘The Fresh Guy’ in Big League (2004) 32: Here’s something pretty spoft! Git this busher!
1915		T.A. Dorgan Indoor Sports 22 July [synd. cartoon] Some busher cut that — They couldn’t a done better with a bowl over that bone head .
1916		J. Lait ‘Annye’s Ma’ in Beef, Iron and Wine (1917) 284: Props, stuttering about the gluttony of pedantic players (fussy bushers) for inconsequential minutiae.
1925		R. Lardner ‘Women’ in Coll. Short Stories (1941) 150: Too damn cute for a busher like you to get smoked up over.
1931		W.N. Burns One-Way Ride 161: His success, they sneered, was an accident. He was a busher.
1948		Life 5 Apr. 21/1: During the past several weeks these raw bushers [...] have been subjected to microscopic scrutiny for major-league aptitude [DA].
1953		L. Uris Battle Cry (1964) 292: They’re big leaguers and you’re just a busher.
1961		L. Schecter Roger Maris 71: ‘That —. He’s bush, the biggest busher who ever made the major leagues’.
1986		S. King It (1987) 76: You’re being a fucking busher, and I don’t like it. [Ibid.] 77: I’m never going to forget you bushed out on me, Rich.