Green’s Dictionary of Slang

roundheels n.

also roundheel
[all fall over easily; the image is of pivoting on the rounded heel]

1. [1920s+] (US) an inferior prize-fighter; also fig. use.

2. [1920s+] (also little Miss Roundheels, little roundheels, Miss Roundheels) a promiscuous woman (cf. light heels n.; short heels n.).

3. [1970s+] (US gay/prison) a victimized young inmate, forced into homosexuality.