The Collaborative International Dictionary of English v.0.48:

Femininity \Fem`i*nin"i*ty\, n.
   1. The quality or nature of the female sex; womanliness.
      [1913 Webster]

   2. The female form. [Obs.]
      [1913 Webster]

            O serpent under femininitee.          --Chaucer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

femininity
    n 1: the trait of behaving in ways considered typical for women
         [syn: femininity, muliebrity] [ant: masculinity]

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "femininity":
   distaff side, fair sex, female sex, femaleness, gender, maleness,
   masculinity, second sex, sex, softer sex, weaker sex,
   weaker vessel, woman, womanhood, womankind, women, womenfolk,
   womenfolks