Green’s Dictionary of Slang

(US) having big breasts; thus by stereotyping, promiscuous.

1984		Benjamin & Pearl Limericks Down Under 59: On alternate nights / Slips into tights / And is buxom and bouffant and booby.
1997–2001		Online Sl. Dict. 🌐 booby adj 2. promiscuous. (‘That girl is so booby!’).
2007		R. Milward Apples (2023) 137: Rachel [...] in a mini-skirt and a very booby top — she was cruising for a spiking.