i Register
In some senses, negress is marked as dated, literary. Watch for register when choosing this word.
noun
A black female.
Directly they were trotted off in their little pea-green and gilt carriage, guardian negress and all, I went into the shop, about which I had all this time been loafingly prowling, and called, clapping my hands, for some violet sherbet, […]
1995, A. J. Verdelle, The Good Negress (book title)
noun
Alternative letter-case form of negress.