Source : Webster's Revised Unabridged Dictionary (1913)

Masculinity \Mas`cu*lin"i*ty\, n.
   The state or quality of being masculine; masculineness.

Source : WordNet®

masculinity
     n 1: the properties characteristic of the male sex [syn: {maleness}]
          [ant: {femaleness}]
     2: the trait of behaving in ways considered typical for men
        [ant: {femininity}]