___ C. J. Walker, first American woman to become a self-made millionaire, per Guinness (5)
I believe the answer is:
madam
(Other definitions for madam that I've seen before include "pompous young lady?" , "Term of address to a woman" , "What you would call a female customer (or a spoiled girl!)" , "Woman running a brothel" , "How one may address a woman" .)