1: an ornamental tuft (as of feathers) especially on a helmet.
2: dash or flamboyance in style and action: verve.
[Origin: Middle French pennache, from Old Italian pennacchio, from Late Latin pinnaculum small wing, related to pinnacle.]
“Potential enemy?” Ponce de Leon made a face. “It lacks panache. I prefer to be called ‘rogue’ or ‘outlaw’.” – Unbound, Jim C. Hines.