In the slang of the
post-WWII era, a woman who is either a
lesbian, ugly/old/unattractive, or just plain unwilling to sleep with men through prudery or distaste. Occasionally,
prostitutes were also said to be of this type, since they charged for what a healthy, happy girl would (at least in theory) give for free. Man-haters were said to be suffering from
penis envy, and lived drab, wretched lives, trying to live as a man did, at least until the man with the
Miracle Member came and swept them off their feet (or they committed
suicide when the same thing happened to their
roommate).
Usually the term was used jocularly, as in "You wouldn't be a man-hater, would you?" in an attempt to salvage a failed pass.