For a slur to go deep like that it has to actually mean something in a historical context. N word was often used in slavery and jim crow times. I don't know if I could think of a single word to incapsulate it, but something harkening back to times of female subjugation would probably work best. Something along the lines of "Baby maker" "Sack of holes," etc. Something better than that of course, but still. "Whore" or "Slut" are things that ring of an age of sexual freedom, which is the opposite of what we're trying ti bring to mind.