Panache. panache |pəˈnaSH, -ˈnäSH| noun 1 flamboyant confidence of style or manner: he entertained Palm Springs society with great panache. 2 historical a tuft or plume of feathers, esp. as a headdress or on a helmet. ORIGIN mid 16th cent.: from French, from Italian pennacchio, from late Latin pinnaculum, diminutive of pinna ‘feather.’