Green’s Dictionary of Slang

nailhead n.

[her tightly curled hair supposedly resembles a collection of SE nail heads]

(US black) an unattractive woman, esp. one with short, nappy hair.

Show quotations
[US]B. Jackson Get Your Ass in the Water (1974) 148: Now there was Nailhead, Railhead, Long-Drinkawater.
[US]E. Folb Runnin’ Down Some Lines 144: Synonyms for chickenhead are [...] hen, thunder chicken, nail head and short nails.