Lewis & Short

impĕtŭōsus, a, um, adj. [impetus], impetuous, violent, Epit. Iliad. 919.
Hence, adv.: impĕtŭōsē (inp-), violently, impetuously: contendit ad moenia, Auct. de Prog. Aug. 5: Acron ad Hor. C. 1, 29, 11.