Green’s Dictionary of Slang

a constable; ‘Mr Thingstable, Mr Constable, a ludicrous affectation of delicacy in avoiding the first syllable in the title of that officer, which in sound has some similarity to an indecent monosyllable’ (Grose, 1785).

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.