little woman vs weaker sex

little woman

noun
  • Used other than figuratively or idiomatically: see little, woman. 

  • A female person with dwarfism, or short stature resulting from a medical condition. 

  • A wife. 

weaker sex

noun
  • Used other than figuratively or idiomatically: see weaker, sex. 

  • Women; the female gender. 

How often have the words little woman and weaker sex occurred in a corpus of books? (source: Google Ngram Viewer )