im·pet·u·os·i·ty \(ˌ)imˌpechəˈwäsəd.ē, əm-, -sətē, -i\noun (-es) Etymology: Middle French impetuosité, from Old French, from Late Latin impetuosus + Old French -ité- -ity 1.: the quality or state of being impetuous < the impetuosity of his proposal — Louis Auchincloss > 2.: an impetuous action or impulse < a man driven by impetuosities and whims >