fu·ri·os·i·ty \ˌfyu̇rēˈäsəd.ē\noun (-es) Etymology: Middle English furiosite, from Middle French or Late Latin; Middle French furiosité, from Late Latin furiositat-, furiositas, from Latin furiosus + -itat-, -itas -ity 1.Scots law: insanity 2.: the quality or state of being furious : fury