Green’s Dictionary of Slang

1. the tongue; the mouth.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Chaffer The Tongue. Cant.
1821		Egan Life in London (1869) 264: If you’ll keep your chaffers close [...] you shall hear all about it.
1830		Egan Finish to the Adventures of Tom and Jerry (1889) 193: Shut up your chaffer, and tip.
1842		Whip & Satirist of NY & Brooklyn (NY) 8 Jan. n.p.: The Tamworth men now let loose their chaffers.
1848		Flash Dict. in Sinks of London Laid Open.
c.1850		Duncombe New and Improved Flash Dict.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1890		C. Hindley Vocab. and Gloss. in True Hist. of Tom and Jerry.

2. the throat.

1827		Pierce Egan’s Life in London 25 Feb. 869/: The Patlanders, who had been rather silent [...] now gave their Chaffers a holiday, singing ‘O’Nale for a hundred’.
1832		Egan Bk of Sports 25: He napt a rum one between the chaffer and the sneezer.

3. (also chafferer) one who banters or teases, a teaser.

1827		Egan Anecdotes of the Turf, the Chase etc. 180: She possessed the gift of the gab [...] and, amongst her equals, was viewed as as an out-and-out chaffer.
1832		Egan Bk of Sports 54: ‘Intrude, my dear fellow,’ replied the Chaffer, ‘I beg you will not mention it?’.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 327/2: One of these men had a wife who used to sell for him, – she was considered to be the best ‘chaffer’ on the road; [...] her language abounded with obscenity.
1877		Temple Bar 536: An actor of very moderate abilities, and so remarkably ill-favoured in person as to be the constant butt of the chaffers in the pit [F&H].
1912		E. Pugh City Of The World 36: Middlesex Street, still popularly known as Petticoat Lane, then a seething mass of chafferers.

4. (UK und.) a street seller who specializes in last dying speeches, true confessions and similar melodramas.

1858

Home News for India 17 Apr. 19/1: The prisoner Benjamin is a well-known ‘chaffer’ [...] the class of street-mendicants, who go about making appeals to the public in a loud voice [...] It is considered the most productive branch of the mendicant's calling.