The Collaborative International Dictionary of English v.0.48:

machismo \machismo\ n.
   1. A strong, and by some considered exaggerated, sense of
      manly pride, associated with an attitude that the proper
      expression of masculinity includes virility, courage, and
      an entitlement to dominate, especially over women.
      [PJC]

   2. An exaggerated sense of power entitling one to dominate
      others; as, the civilian authorities occasionally need to
      rein in the military's machismo.
      [PJC]

WordNet (r) 3.0 (2006):

machismo
    n 1: exaggerated masculinity