Green’s Dictionary of Slang

a ruffian, a hooligan, a thug.

1876		Sheffield Dly Teleg. 30 Aug. 3/4: An Amateur Bash-Bazouk in Sheffield. Edwin Newton [...] will be charged [...] with maliciously wounding Samuel Gill [...] and also with assaulting the police.
1904		G.B. Shaw John Bull’s Other Island Act III: In Roscullen a yeoman means a sort of Orange Bashi-Bazouk.
1904		Edinburgh Eve. News 16 Sept. 2/5: [She] was fined 10s. for using improper language [...] having called her husband a bleary-eyed Kaffir, a Bashi-Bazouk, a Bulgarian atrocity, an ugly moneky, a baboon.
1930		Eve. Teleg. 12 Feb. 6/5: Good Coat-makers Wanted. No Bashi-Bazouks or Gutter-Warblers Need Apply.
1936		Mencken letter 10 Sept. in Riggio Dreiser-Mencken Letters II (1986) 611: If the Hearst bashibazouks attempt to lynch you we’ll protect you.
c.1939		B. Bennett ‘Me and a Spade’ in Billy Bennett’s Fifth Budget 13: There were [...] Chinese, and knock-knees, and buzza-bazooks, / That only a mother could tell.
1962		H. Livings Nil Carborundum (1963) Act III: Watch that Bashi Bazook there doesn’t kill anyone, coporal.
1966		P. Boyle At Night All Cats Are Grey 72: When the bloody bashi-bazouk gets his breath back he reaches for the pint again.
1977		(con. 1941) R. Beilby Gunner 15: Yorba was a guerilla with the manner of a clown and the instincts of a Bashi-bazouk.