Source : Webster's Revised Unabridged Dictionary (1913)

Furious \Fu"ri*ous\, a. [L. furiosus, fr. furia rage, fury: cf.
   F. furieux. See {Fury}.]
   1. Transported with passion or fury; raging; violent; as, a
      furious animal.

   2. Rushing with impetuosity; moving with violence; as, a
      furious stream; a furious wind or storm.

   Syn: Impetuous; vehement; boisterous; fierce; turbulent;
        tumultuous; angry; mad; frantic; frenzied. --
        {Fu"ri*ous*ly}, adv. -- {Fu"ri*ous*ness}, n.

Source : WordNet®

furiously
     adv 1: (of the elements) in a wild and stormy manner; "winds were
            blowing furiously"
     2: in a manner marked by extreme or violent energy; "the boys
        fought furiously"; "she went peddling furiously up the
        narrow street"
     3: in an impassioned or very angry manner; "she screamed
        furiously at her tormentors"