Green’s Dictionary of Slang

a woman; the inference is of promiscuity if not actual prostitution.

1932		V.F. Nelson Prison Days and Nights 35: These visits, especially from the broadies, are a pain in the whatsis.
1952		(con. 1948) G. Mandel Flee the Angry Strangers 104: If it’s the broadie I seen you wit this mornin. She’s [...] married.
1963		A.S. Fleischman Venetian Blonde (2006) 232: There was a white Jaguar parked across the street and the broadie at the wheel tapped the horn.
1967		E. Shepard Doom Pussy 172: I’m probably just getting you heated up and sending you into the arms of some broadie over there.
1987		Growing Pains [ABC-TV] So who are these two good-lookin’ broadies, eh? [HDAS].