horrĭsŏnus

I. sounding dreadfully, that makes a horrid sound (poet.): fretum, Cic. poët. Tusc. 2, 10, 23; cf. flatus, Luc. 2, 455: fragor, Lucr. 5, 109: fremitus, Verg. A. 9, 55: cardo, id. ib. 6, 573: buxus, Val. Fl. 2, 584: flagellum, id. 7, 149.