A crooked or hump-backed man. These unhappy people afford great scope for vulgar raillery; such as, ‘Did you come straight from home? if so, you have got confoundedly bent by the way.’ ‘Don’t abuse the gemman,’ adds a by-stander, ‘he has been grossly insulted already; don’t you see his back’s up?’ Or someone asks him if the show is behind; ‘because I see,’ adds he, ‘you have the drum at your back.’ Another piece of vulgar wit is let loose on a deformed person: If met by a party of soldiers on their march, one of them observes that that gentleman is on his march too, for he has got his knapsack at his back. It is said in the British Apollo, that the title of lord was first given to deformed persons in the reign of Richard III. from several persons labouring under that misfortune being created peers by him; but it is more probably derived from the Greek word [GREEK: lordos], crooked.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
See also the definition in Nathan Bailey's 1736 dictionary of canting and thieving slang.
To Lope * LouseNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes