Definition of "panache"

I had taken the panache from my shako so that it might escape notice, but even with my fine overcoat I feared that sooner or later my uniform would betray me.

1896, Arthur Conan Doyle, chapter 4, in The Exploits of Brigadier Gerard

One old gentleman, who was in the habit of reading a Paris newspaper and knew things, chuckled gleefully to everybody that Alcée’s conduct was altogether chic, mais chic. That he had more panache than Boulanger. Well, perhaps he had.

1894, Kate Chopin, “At the 'Cadian Ball”, in Bayou Folk

Cyberpunk caters to the wish-fulfillment requirements of male teen-agers, but this is a job that can be done with varying degrees of panache, and there is currently no more accomplished caterer than William Gibson.

1988 December 11, Thomas M. Disch, “Lost in Cyberspace”, in The New York Times‎