Lewis Short
(adjective) : ef-fĕrus, a, um
* Very wild, fierce, savage (poet. and post-class.; freq. in Verg.): proles,Lucr. 2, 604; cf. juventus,Verg. A. 8, 6: Dido,id. ib. 4, 642: Chimaera,id. ib. 7, 787: mens Caci,id. ib. 8, 205; cf.: vis animi,id. ib. 10, 898: corda,Val. Fl. 1, 798: ira,id. 5, 517: virtus Bebrycis,id. 2, 648: facta tyranni,Verg. A. 8, 484: facinus,Sen. Phoen. 264; Flor. 4, 12, 12; 4, 12, 48; Sen. Element. 1, 13, 4.
Charlton T. Lewis, Charles Short, A Latin Dictionary