The Collaborative International Dictionary of English v.0.48:

Manliness \Man"li*ness\, n.
   The quality or state of being manly.
   [1913 Webster]

WordNet (r) 3.0 (2006):

manliness
    n 1: the trait of being manly; having the characteristics of an
         adult male [syn: manfulness, manliness, virility]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "manliness":
   Dutch courage, boldness, braveness, bravery, chivalrousness,
   chivalry, conspicuous gallantry, courage, courageousness,
   doughtiness, gallantness, gallantry, gallantry under fire,
   gentlemanlikeness, gentlemanliness, greatheartedness, heroicalness,
   heroism, intrepidity, intrepidness, knightliness, lionheartedness,
   maleness, manfulness, manhood, manlihood, manlikeness, mannishness,
   martial spirit, masculineness, masculinity, military spirit,
   pot-valor, prowess, soldierly quality, stalwartness,
   stoutheartedness, stoutness, valiance, valiancy, valor,
   valorousness, virtue