Green’s Dictionary of Slang

1. (also cadie, cawdy) a person who frequents tavern yards and persuades customers to patronize another inn, for which they are paid by its landlord.

1726		E. Burt Letters from Scotland I (1754) 26: I then had no Knowledge of the Cawdys, a very useful Black-Guard, who attend the Coffee-Houses and publick Places to go of Errands; and though they are Wretches, that in Rags lye upon the Stairs, and in the Streets at Night, yet are they often considerably trusted.
a.1774		Fergusson Poems (1821) 151: A cadie wi his lantern, / Been gleg eneugh to hear them bant'rin'.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc.

2. a thief’s assistant.

1811		Lex. Balatronicum n.p.: Caddee. A helper. An under-strapper.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 20: One who performs the minor parts of a joint robbery ‘is but a caddee in the business.’ Any inferior actor in a thing.

3. a passer-on of counterfeit money.

1984

Partridge DSUE (8th edn) 172/2: ‘ca.1820–80‘.