Green’s Dictionary of Slang

no bon adj.

no good.

[1881		Newcastle Courant 25 Nov. 6/5: That’s more like Bill the Smasher than crying no bone].
1916		Somme-Times 31 July (2006) 119/2: The Kaiser once said at Peronne / That the Army we’d got was ‘no bon.’.
1919		C.H. Thorp Handful of Ausseys 110: ‘How’re things?’ ‘Up to — no blanky bon, diggers; this messing round and friggin’ about with the blanky pack-up.
1919		C.H. Thorp Handful of Ausseys 269: Big stuff’s [i.e. large calibre shells] no bon — finney — na poo — alley toot-sweet fer a bloke.
1920		‘Sapper’ Bulldog Drummond 40: For a fellah to stop his car by braking so hard he locks both back wheels is no bon, as we used to say in France.
1925		N. Lucas Autobiog. of a Thief 86: I ain’t working just now – no bon, just yet.
1999		G. Seal Lingo 58: tray bon for very good which commonsensically in English at least led to no bon for no good.