Source : Webster's Revised Unabridged Dictionary (1913)

Manful \Man"ful\, a.
   Showing manliness, or manly spirit; hence, brave, courageous,
   resolute, noble. `` Manful hardiness.'' --Chaucer. --
   {Man"ful*ly}, adv. -- {Man"ful*ness}, n.

Source : WordNet®

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