Green’s Dictionary of Slang

1. in horseracing, one who keeps an eye on horses when training, the health of jockeys, the orders given by owners, etc.

1821		Egan Life in London (1869) 61: Talking with the touters and jockeys at Newmarket.
1832		Egan Bk of Sports 184: It may also be necessary, if it can be fathomed from the Touters, whether the jockey is to ride ‘according to orders.’.

2. (UK Und.) a thief’s lookout.

1828		G. Smeeton Doings in London 253: Some of them act as ‘touters’ to those who may have got the ‘swag,’ and the moment they find that the thief is ‘grabbed’ (apprehended), they run off.
1843–44		Dickens Martin Chuzzlewit (1995) 578: Nor did it mark him out as the prey of ring-droppers, pea and thimble-riggers, duffers, touters, or any of those bloodless sharpers, who are, perhaps, a litle better known to the Police.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1864, 1867, 1870		Hotten Sl. Dict.

3. (UK und.) a woman who accompanies a dress-lodger under dress n. to prevent her escaping in her borrowed, expensive clothes and checking on her paid encounters.

1848

Paul Pry 27 Nov. n.p.: Beside [the dress lodger] stands a shabbily-dressed, coarse, vulgar, face-seamed hag—young or old, she is the same [...] she is the touter; she travels abroad by night with this lovely girl, who sells herself to any that may be in the way, and is an account-keeper of the revolting profits of that most fair body.

4. one who frequents courts and recommends the solicitor who pays him to do so.

1850

Fast Man 9:1 n.p.: County Court Solicitors [...] are pettifoggers of the lowest class and sharpest practice, and support a number of those dirty nuisances called ‘touters.’ Let any of our readers attend a Court and they will be besieged by these fellows.

5. the equivalent of SE tout, one who solicits for custom on behalf of criminal boarding houses, etc.

1850		Life in Boston & N.Y. (Boston, MA) 6 Apr. n.p.: The ‘touters’ who loaf about railway depots, and steambot landings, to trap unwary passengers into the toils of the lowest of the low boarding houses.
1895		Crowe Aus. Sl. Dict. 88: Touters, hotel or boarding house runners.

6. a guide, e.g. to a tourist site.

1868

Sportsman 11 Mar. 2/1: Notes on News [...] [O]ne of the‘Westminster Abbey ‘touters,’ has been very properly sent for trial on a charge of fraudulently obtaining 2s. from two ladies false pretence of showing them over the Abbey.