Lewis & Short

vĭŏlens, entis, adj. [vis], impetuous, vehement, furious, violent (mostly poet. and in post-Aug. prose, whereas violentus is class.): Aufidus, Hor. C. 3, 30, 10: victor equus, id. Ep. 1, 10, 37; so (with ferus), Pers. 5, 171.