Lewis & Short

vōcĭfĕro, āre, 1, v. a., rare collat. form of vociferor: crescere turba et vociferare ex omnibus locis, Liv. 7, 12, 14; cf. id. 10, 28, 12, s. v. vociferor: qui vociferant saepe, Varr. R. R. 3, 9, 5.
Pass. impers.: vociferatum ferociter, Liv. 24, 21, 2.