roundheel

round-heeled

R5349850 (round′hēld′)adj. Derogatory Sexually promiscuous. Used of a woman.
[From roundheels, a boxer who is easy to knock out, from the image of a promiscuous woman frequently being on her back.]
round′heel′ n.

roundheel

(ˈraʊndˌhiːl) nslang an eagerly immoral woman