Green’s Dictionary of Slang

1. a promiscuous woman.

1943		cited in Cassidy & LePage Dict. Jam. Eng. (1980) 134/2: cubba [...] sometimes a slut.
1989		C. Hyatt When Me Was A Boy 103: All dem other ones used to tease ‘Miss Cubba’ an ‘Mother Warner’ an ‘Bun-Down-Cross’.

2. an effeminate man.

1943		cited in Cassidy & LePage Dict. Jam. Eng. (1980) 134/2: cubba A womanish man.
1955		cited in Cassidy & LePage Dict. Jam. Eng. (1980) 302/1: miss cubba [...] a man who meddles in woman’s affairs.
1989		C. Hyatt When Me Was A Boy 152: The ‘Johnny Cubba’ is suppose to be the invention of what everybody did agree was the best floor cleaner [...] Can you imagine how I did frighten when I fine out that Miss Cubba was a man?