vociferous UK /vəʊˈsɪfəɹəs/US /voʊˈsɪfəɹəs/ adjective2 •Making or characterized by a noisy outcry; clamorous.They crowded around him with vociferous welcome, Brown leading in a series of wild cheers. — 1909 •Vocally and forcefully opinionated.Not even the most vociferous advocates of reform were willing to go to such lengths. formsmore vociferous · most vociferous