Source : Webster's Revised Unabridged Dictionary (1913)

Towering \Tow"er*ing\, a.
   1. Very high; elevated; rising aloft; as, a towering height.
      --Pope.

   2. Hence, extreme; violent; surpassing.

            A man agitated by a towering passion. --Sir W.
                                                  Scott.

Source : WordNet®

towering
     adj : of imposing height; especially standing out above others;
           "an eminent peak"; "lofty mountains"; "the soaring
           spires of the cathedral"; "towering iceburgs" [syn: {eminent},
            {lofty}, {soaring}]