c.1600, from Fr. férocité, from L. ferocitatem (nom. ferocitas) "fierceness," from ferocis, an oblique case of ferox "fierce, wild-looking," a derivative of ferus "wild" (see fierce
) + -ox, -ocem (gen. -ocis), a suffix meaning "looking or appearing" (cognate with Gk. ops "eye, sight").