Green’s Dictionary of Slang

1. a pimp.

[1513		G. Douglas Eneados ‘Prologe’ Bk IV (1553) lxxiiii: Of brokaris and sic baudry hou suid I write [...] Sic pode makrellis, for Lucifer bene leche].
1607		A Knight’s Conjuring Ch. VI H1: Tell all the Brokers in Long-lane, Houns ditch, or else wher, with all the rest of their Colleagued Suburbians, that deal vpon ouer-worne commodities [...] that they lye safe enough.
1662		‘M.W.’ Marriage Broaker II ii: ’Tis not an hour since the old Placket-broaker Our neighbour Derrick sends for me to a tavern.
1754		Scoundrel’s Dict. 23: The Hue and Cry, to shun, we crept, / in Hedges where we lay’d. / To the Brokers then my Hedge-bird flies.

2. (drugs) a go-between in a drug deal or in any illegal transaction.

1931		Irwin Amer. Tramp and Und. Sl. 37: Broker. – A narcotic peddler ; the go-between who buys the drug from the man higher up, or who acts as the agent for a ‘ring,’ and sells, at high prices and in small lots, to the addict.
1959		J.E. Schmidt Narcotics Lingo and Lore.
1971		T. Thackrey Thief 333: They were the guys who supplied the pushers. The brokers.
1996		J. Cameron It Was An Accident 24: I was a broker one or two times. Make the intros you know?
2001		ONDCP Street Terms 4: Broker — Go between in a drug deal.