Panache is a word of French origin that carries the connotation of a flamboyant manner and reckless courage.
The literal translation is a plume, such as is worn on a hat or a helmet, but the reference is to King Henry IV of France. Pleasure-loving and cynical, but a brave military leader and the best-loved of the kings of France, he was famed for wearing a striking white plume in his helmet and for his war cry: "Follow my white plume!" (Fr. "Ralliez-vous à mon panache blanc!").
Panache is now used to describe someone who has a dashing confidence of style, like wearing a top-hat, or shows a certain flamboyance and courage, such as, wearing a monocle, and is a familiar word now in English. Its meaning has also been extended to include anything capable of displaying such attributes.