The Collaborative International Dictionary of English v.0.48:

Virago \Vi*ra"go\ (?; 277), n.; pl. Viragoes. [L. virago,
   -intis, from vir a man. See Virile.]
   1. A woman of extraordinary stature, strength, and courage; a
      woman who has the robust body and masculine mind of a man;
      a female warrior.
      [1913 Webster]

            To arms! to arms! the fierce virago cries. --Pope.
      [1913 Webster]

   2. Hence, a mannish woman; a bold, turbulent woman; a
      termagant; a vixen.
      [1913 Webster]

            Virago . . . serpent under femininity. --Chaucer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

virago
    n 1: a noisy or scolding or domineering woman
    2: a large strong and aggressive woman [syn: amazon, virago]