The Collaborative International Dictionary of English v.0.48:

Panache \Pa*nache"\, n. [F., fr. L. penna a feather. See Pen a
   feather.]
   1. A plume or bunch of feathers, esp. such a bunch worn on
      the helmet; any military plume, or ornamental group of
      feathers.
      [1913 Webster]

            A panache of variegated plumes.       --Prescott.
      [1913 Webster]

   2. A pleasingly flamboyant style or manner; flair[4]; verve.
      [PJC] Panada

WordNet (r) 3.0 (2006):

panache
    n 1: distinctive and stylish elegance; "he wooed her with the
         confident dash of a cavalry officer" [syn: dash, elan,
         flair, panache, style]
    2: a feathered plume on a helmet

Moby Thesaurus II by Grady Ward, 1.0:

66 Moby Thesaurus words for "panache":
   animation, blatancy, boldness, brazenness, brio, chic,
   colorfulness, crest, crudeness, cultivation, dash, dazzle,
   dazzlingness, eclat, elan, energy, enthusiasm, extravagance,
   extravaganza, extravagation, feather, flagrancy, flair,
   flamboyance, flashiness, flourish, gaiety, garishness, gaudery,
   gaudiness, glare, glitter, good taste, gorgeousness, gusto, hackle,
   jauntiness, jazziness, liveliness, loudness, luridness,
   meretriciousness, obtrusiveness, pinion, plume, plumule, quill,
   savoir faire, scapular, self-assurance, sensationalism,
   shamelessness, showiness, smartness, sophistication, spirit,
   sportiness, style, swagger, tawdriness, topknot, tuft, verve,
   vigor, vulgarness, zest