Source : Webster's Revised Unabridged Dictionary (1913)

Tremendous \Tre*men"dous\, a. [L. tremendus that is to be
   trembled at, fearful, fr. tremere to tremble. See {Tremble}.]
   Fitted to excite fear or terror; such as may astonish or
   terrify by its magnitude, force, or violence; terrible;
   dreadful; as, a tremendous wind; a tremendous shower; a
   tremendous shock or fall.

         A tremendous mischief was a foot.        --Motley.

   Syn: Terrible; dreadful; frightful; terrific; horrible;
        awful. -- {Tre*men"dous*ly}, adv. --
        {Tre*men"dous*ness}, n.

Source : WordNet®

tremendously
     adv : extremely; "he was enormously popular" [syn: {enormously}, {hugely},
            {staggeringly}]