nubbin, n. — Green’s Dictionary of Slang

nubbin n.

[play on SE nubbin, the remains of something that has been worn away, e.g. a pencil; ult. a dwarfed or imperfect ear of maize]

1. (US black) the penis.

1909		in Randolph & Legman Ozark Folksongs and Folklore (1992) II 765: Down goes her hand / A-feeling of your nubbin.
c.1940		‘Amos ’n Andy’ [comic strip] in B. Adelman Tijuana Bibles (1997) 72: Releasing Andy’s nubbin which by now is in a helluva condition.
1949		in Randolph & Legman Ozark Folksongs and Folklore (1992) I 407: All them gals is after my nubbin, / Butter don’t come, they keep on a-rubbin’.

2. (US black) a fool, a simpleton.

1934

Z.N. Hurston Jonah’s Gourd Vine (1995) 43: You ole battle-hammed, slew-foot, box-ankled nubbin, you!