Panache is a nice thing to have, it seems, when you are a rock star. Not so nice when you display it when being cought in a lie & cheating (cool how the Atlantic fits the panache into the first sentence in this article about Qusay Trump Jr.).
This is one of those French words the English have imported, but they have changed the semantics slightly to carry the connotation of flamboyant manner and reckless courage. Originally a panache just meant a plume, like the feathers people used to sport on their hats. According to Wikipedia the English use of the term is a reference to King Henry IV of France, who wore a white feather in his helmet and went into battle with the cry "Follow my white plume!" (French: "Ralliez-vous à mon panache blanc!"). Might even be true.
The first time I read that word it was as a description of Freddy Mercury on stage, now it has reached the Trump family™ . Who would have thought a feather could sink so low, so fast?
And now my problem: How do you express that concept in Spanish or German? I don't know.